A high-flux self-cleaning composite nanofiber membrane and its device

Abstract

This invention relates to a high-flux composite nanofiber membrane and its device for bilirubin removal. By sequentially constructing two different casting solutions—one a hydrophilic layer with an imine coating and the other a photocatalytic self-cleaning hydrophilic layer—the nanofiber membrane is endowed with bilirubin removal, photocatalytic self-cleaning, and high-flux capabilities. The main photocatalytic modifier uses copper-carbon materials as copper and carbon sources, and nitrogen-containing organic compound g-C3N5 as a precursor, prepared via thermal polycondensation. The modifier is a hydrophilic material. The advantages of this invention are that the synthesis method of the modifier is simple, the operation is controllable, and the materials are readily available; the composite membrane improves the surface hydrophilicity and bilirubin degradation efficiency, significantly increasing the flux, which is beneficial for the long-term stable operation of the membrane, efficiently removing bilirubin, and exhibiting good oil-water separation efficiency.

Description

Technical Field

[0001] This invention relates to a high-flux composite nanofiber membrane and its device for bilirubin removal, belonging to the field of separation membrane preparation technology. The modified membrane has advantages such as high pure water flux, high bilirubin removal efficiency, good oil retention performance and excellent light response effect, and is suitable for the field of bilirubin removal. Background Technology

[0002] In today's society, bilirubin removal and oil-water separation are of paramount importance in the environmental and medical fields, respectively. Hyperbilirubinemia poses a threat to human health, especially the nervous system, while bilirubin-containing medical wastewater can severely pollute soil and groundwater, endangering human health. Simultaneously, the discharge of oily wastewater also causes serious damage to the aquatic environment. Traditional bilirubin removal and oil-water separation methods have various limitations and are difficult to operate efficiently under complex conditions.

[0003] Self-cleaning electrospun nanofiber membranes, with their unique structure granted by electrospinning technology, show broad application prospects in bilirubin removal and oil-water separation. These nanofibers possess excellent filtration and adsorption capabilities, effectively handling problems such as emulsified oils. Their self-cleaning properties reduce contaminant accumulation, maintain performance stability, extend service life, and lower maintenance costs. This provides a new technological approach and solution for achieving safe and effective bilirubin removal and efficient, sustainable oil-water separation. However, a series of technical and process challenges still need to be overcome in practical application and promotion.

[0004] Currently, in-depth research has been conducted both domestically and internationally on the application of nanofiber membranes in bilirubin removal. Patent CN202110338951.X discloses a nanofiber bilirubin adsorbent and its preparation method. This adsorbent utilizes multiple interaction sites, including electrostatic adsorption, hydrogen bonding, and π-π interactions, to specifically recognize bilirubin molecules. However, research on the removal of bilirubin from wastewater, and the removal of oil and bilirubin from oily wastewater under complex conditions, is still insufficient. Therefore, it is necessary to develop a high-throughput composite nanofiber membrane that can effectively remove bilirubin while simultaneously meeting the requirements for oil removal, thereby filling the research gap in this field. Summary of the Invention

[0005] The purpose of this invention is to address the current problem of membranes being easily fouled and unable to meet the requirements of membrane separation. A high-flux composite nanofiber membrane for bilirubin removal has been prepared and a device has been designed. The prepared hydrophilic modified nanofiber membrane has advantages such as high efficiency in removing bilirubin, high flux, and good protein permeation in the device. It is suitable for the separation process of oil and water containing bilirubin and can ensure excellent separation effect and long-term stable operation.

[0006] The high-flux composite nanofiber membrane for bilirubin removal prepared in this invention is produced by first modifying the membrane using a blending modification method, then preparing the membrane by electrospinning the spinning solution, and finally obtaining the coating by immersion. The membrane is prepared through the following steps:

[0007] Step 1) Weigh a certain amount of nitrogen-containing organic matter using an analytical balance and dissolve it in a beaker. Measure an appropriate amount of distilled water using a graduated cylinder and dissolve it in the beaker. Then weigh a certain amount of copper-containing carbon material into the beaker. Place the beaker on a magnetic stirrer, cover the mouth of the beaker with plastic wrap, and stir at room temperature for 3 hours. Then place it in an oven (<80 ℃) to completely dry the sample. Weigh the obtained solid sample, grind it in an agate mortar, place it in a crucible, and heat it in a muffle furnace to 550 ℃ at a heating rate of 5 ℃ / min. -1 The mixture was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container to obtain Cu / C-C3N5. The nitrogen-containing organic compound was one or more of 3-amino-1,2,4-triazole, melamine, thiourea, dicyandiamine, and urea. The copper-containing carbon material was one or more of cuprous glycinate, copper glycinate, Prussian blue, and copper-carbon alloy nanoparticles. The copper-containing carbon material accounted for 0.5% to 5% of the total mass of the calcined material.

[0008] Step 2) Preparation of spinning solution: The spinning solution is prepared by mixing the first and second strands of materials according to the mass percentage of their components. The components of the first strand are: base material 8-15%, TPU 6-10%, polyvinylpyrrolidone 1-10%, carboxymethyl cellulose 0.5-1%, and the remainder is N,N-dimethylformamide. The polyvinylpyrrolidone and carboxymethyl cellulose of the first strand are dissolved in N,N-dimethylformamide and heated and stirred until dissolved. After dissolution, the base material and TPU of the first strand are added, and heating and stirring are continued for 1.5-3.5 hours until completely dissolved. The components of the second strand are: base material 11-15%, TPU... 4-10%, Cu / C-C3N5 0.5-1.5%, polyvinylpyrrolidone 1-10%, carboxymethyl cellulose 0.5-1%, and the remainder is N,N-dimethylformamide; dissolve Cu / C-C3N5, polyvinylpyrrolidone and carboxymethyl cellulose of the second material in N,N-dimethylformamide and heat and stir. After dissolution, add the substrate of the second material and TPU and continue heating and stirring for 1.5-3.5 h until completely dissolved.

[0009] Step 3) Preparation of composite nanofiber membrane: The spinning solution from step (2) was spun into a membrane using electrospinning. The DC voltage of the spinning machine was set to 16-20 KV, the injection pump flow rate was 1.1-1.8 ml / h, and the receiving distance was 16-20 cm. The membrane preparation process involved continuous spinning of two materials sequentially. First, 6-8 ml of the spinning solution of the first material was drawn in, and spinning was carried out for 4-6 h to form a nanofiber substrate membrane with a thickness of 55-85 μm and a pore size of 0.5-1.5 μm. Then, the spinning solution of the second material was quickly spun on the already formed membrane. 4-6 ml of the spinning solution of the second material was drawn in, and spinning was carried out for 3-4 h to form a Cu / C-C3N5 nanofiber membrane modified with polyvinylpyrrolidone and carboxymethyl cellulose with a total thickness of 100-130 μm and a pore size of 0.5-1.5 μm. μm; then the prepared membrane was repeatedly washed with ethanol solution and dried. The dried membrane was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0010] Preferably, in step (2), the substrate is one of polyvinylidene fluoride, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, polystyrene, cellulose and its derivatives.

[0011] Preferably, in step (3), the imine coating is one or more of polyethyleneimine, polyamide-imine, and thiobutylamidine chitosan.

[0012] The reactions involved in the degradation of bilirubin according to the present invention include Cu / C-C3N5 photocatalytic degradation of bilirubin, hydrophilic membrane retention of bilirubin, and PEI coating adsorption of bilirubin.

[0013] For the photocatalytic degradation of bilirubin by Cu / C-C3N5: Under visible light conditions, Cu enhances the light absorption range, enabling the generation of electron-hole pairs through charge separation. Photogenerated electrons are transferred to the conduction band of g-C3N5, contributing to the production of highly oxidizing superoxide radicals (O2). - The photocatalyst converts bilirubin into CO2 and H2O by reacting it with hydroxyl radicals (·OH). The addition of carbon materials improves the absorption range and stability of the photocatalyst, extending its lifespan.

[0014] For hydrophilic membranes to retain bilirubin: The pore size of the hydrophilic membrane is moderate, which can retain larger bilirubin molecules. Hydrophilic groups form hydrogen bonds with the hydrophilic groups inside the bilirubin molecule, causing the bilirubin molecule to be adsorbed on the membrane surface and difficult to pass through the membrane pores.

[0015] For PEI coating to adsorb bilirubin: PEI coating contains positively charged functional groups such as amino groups, which generate electrostatic attraction with the negative charge of bilirubin, causing bilirubin to be adsorbed on the coating surface.

[0016] The high-flux composite nanofiber membrane for bilirubin removal prepared in this invention maintains a pure water flux of 13,000-15,000 L·m³ under the conditions of bilirubin removal rate ≥97.5% and macromolecular oil rejection rate ≥99.5%. -2 ·h -1 This nanofiber membrane exhibits significant bilirubin removal and oil droplet separation effects. Even after multiple bilirubin removal cycles, it maintains excellent performance, providing a reliable solution for efficient bilirubin removal and oil-water separation.

[0017] Beneficial effects:

[0018] Compared with existing technologies, this invention, based on a continuous multi-step spinning method and modification of the membrane by obtaining a coating through immersion, successfully obtains spun membranes with different functions, and has the following advantages and beneficial effects:

[0019] 1. High bilirubin removal efficiency: The modified composite nanofiber membrane of this invention exhibits excellent bilirubin removal performance, with a removal rate as high as 97.5%. By introducing hydrophilic modifying materials and Cu / C-C3N5 modifying materials, the pure water flux of the membrane can reach 13000-15000 L·m. -2 ·h -1 This greatly improves water treatment efficiency and is significantly better than methods that only use photocatalysts to degrade bilirubin.

[0020] 2. Excellent oil retention performance: The modified composite nanofiber membrane has a good oil retention effect, providing a reliable solution for oil-water separation.

[0021] 3. It possesses self-cleaning and anti-fouling properties, exhibiting good long-term operational stability. Through photocatalytic reaction, the nanofiber membrane of this invention possesses anti-fouling properties, extending the membrane's service life. In complex environments, the modified composite nanofiber membrane demonstrates higher stability, effectively and persistently meeting challenges. Attached Figure Description

[0022] Figure 1 In Example 6 of this invention, Cu / C-C3N5

[0023] Figure 2 This invention relates to an apparatus for testing the bilirubin removal rate of high-flux composite nanofiber membranes under light irradiation.

[0024] Figure 3 The schematic diagram of the bilirubin-containing oil-water mixture separation device (6) in the apparatus for testing the bilirubin removal rate of high-throughput composite nanofiber membranes under light irradiation according to the present invention is shown below. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments.

[0026] Example 1

[0027] Step 1) Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.02 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible to 550℃ in a muffle furnace at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0028] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0029] Step 2) The spinning solution is prepared from two materials according to the following component mass percentages: The first material consists of 10% base material, 5% TPU, 5% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. PVP and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved. The second material consists of 11% base material, 5% TPU, 1% Cu / C-C3N5, 5% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. Cu / C-C3N5, PVP, and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved.

[0030] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 17 KV, the injection pump flow rate was 1.5 ml / h, and the receiving distance was 16 cm. The overall film-making process involved two materials being spun sequentially. First, 6 ml of the first material was drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 65 μm and a pore size of 0.6 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 3.5 ml of the second material was drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 100 μm and a pore size of 0.7 μm. The prepared film was then repeatedly washed with ethanol solution and dried. The dried film was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0031] The composite nanofiber membrane has a pure water flux of 13500 L·m⁻¹ -2 ·h -1 The bilirubin removal rate is ≥82.8%, and the large molecular oil rejection rate is ≥97.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0032] Example 2

[0033] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.02 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0034] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0035] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 6% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 1% Cu / C-C3N5, 6% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5, PVP, and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0036] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 18 KV, the injection pump flow rate was 1.4 ml / h, and the receiving distance was 17 cm. The overall film-making process involved two materials being spun sequentially. First, 8 ml of the first material was drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 75 μm and a pore size of 0.7 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 6 ml of the second material was drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 125 μm and a pore size of 0.8 μm. The prepared film was then repeatedly washed with ethanol solution and dried. The dried film was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0037] The composite nanofiber membrane has a pure water flux of 14000 L·m -2 ·h -1 The bilirubin removal rate is ≥83.9%, and the large molecular oil rejection rate is ≥99.2%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high level of pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0038] Example 3

[0039] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.02 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min.-1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0040] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0041] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 8% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 1% Cu / C-C3N5, 8% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5, PVP, and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0042] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 19 KV, the injection pump flow rate was 1.4 ml / h, and the receiving distance was 18 cm. The overall film-making process involved two materials being spun sequentially. First, 8 ml of the first material was drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 85 μm and a pore size of 1.5 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 7 ml of the second material was drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 130 μm and a pore size of 1.5 μm. The prepared film was then repeatedly washed with ethanol solution and dried. The dried film was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0043] The composite nanofiber membrane has a pure water flux of 13500 L·m⁻¹ -2 ·h -1 The bilirubin removal rate is ≥86.1%, and the large molecular oil rejection rate is ≥99.3%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high level of pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0044] Example 4

[0045] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.02 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0046] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0047] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 9% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 1% Cu / C-C3N5, 9% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5, PVP, and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0048] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 17 KV, the injection pump flow rate was 1.6 ml / h, and the receiving distance was 17 cm. The overall film-making process involved two materials being spun sequentially. First, 7 ml of the first material was drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 75 μm and a pore size of 0.7 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 6 ml of the second material was drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 115 μm and a pore size of 0.8 μm. The prepared film was then repeatedly washed with ethanol solution and dried. The dried film was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0049] The composite nanofiber membrane has a pure water flux of 14500 L·m -2 ·h -1 The bilirubin removal rate is ≥91.8%, and the large molecular oil rejection rate is ≥99.4%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high level of pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0050] Example 5

[0051] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.02 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0052] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0053] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: The first material consists of 10% base material, 5% TPU, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. PVP and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved. The second material consists of 10% base material, 5% TPU, 1% Cu / C-C3N5, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. Cu / C-C3N5, PVP, and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved.

[0054] Step 3) The spinning solution from step (2) is spun into a film using electrospinning. The DC voltage of the spinning machine is set to 20 KV, the injection pump flow rate is 1.4 ml / h, and the receiving distance is 20 cm. The overall film-making process involves two materials being spun sequentially. First, 7 ml of the first material is drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 80 μm and a pore size of 0.6 μm. Then, the spinning solution of the second material is quickly spun on the already formed film. 5 ml of the second material is drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 115 μm and a pore size of 0.7 μm. The prepared film is then repeatedly washed with ethanol solution and dried. The dried film is then immersed in PEI solution for 10 min and removed, and then dried for later use.

[0055] The composite nanofiber membrane has a pure water flux of 145,000 L·m -2 ·h -1 The bilirubin removal rate is ≥97.1%, and the large molecular oil rejection rate is ≥98.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0056] Example 6

[0057] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.015 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, place it in a crucible, and heat it in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0058] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0059] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: The first material consists of 10% base material, 5% TPU, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. PVP and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved. The second material consists of 10% base material, 5% TPU, 1% Cu / C-C3N5, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. Cu / C-C3N5, PVP, and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved.

[0060] Step 3) The spinning solution from step (2) is spun into a film using electrospinning. The DC voltage of the spinning machine is set to 20 KV, the injection pump flow rate is 1.4 ml / h, and the receiving distance is 20 cm. The overall film-making process involves two materials being spun sequentially. First, 7 ml of the first material is drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 75 μm and a pore size of 0.6 μm. Then, the spinning solution of the second material is quickly spun on the already formed film. 5 ml of the second material is drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 115 μm and a pore size of 0.65 μm. The prepared film is then repeatedly washed with ethanol solution and dried. The dried film is then immersed in PEI solution for 10 min and removed, and then dried for later use.

[0061] The composite nanofiber membrane has a pure water flux of 150,000 L·m -2 ·h -1 The bilirubin removal rate is ≥97.5%, and the large molecular oil rejection rate is ≥99.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high level of pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0062] Example 7

[0063] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.01 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min.-1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0064] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0065] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: The first material consists of 10% base material, 5% TPU, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. PVP and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved. The second material consists of 10% base material, 5% TPU, 1% Cu / C-C3N5, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. Cu / C-C3N5, PVP, and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved.

[0066] Step 3) The spinning solution from step (2) is spun into a film using electrospinning. The DC voltage of the spinning machine is set to 20 KV, the injection pump flow rate is 1.4 ml / h, and the receiving distance is 20 cm. The overall film-making process involves two materials being spun sequentially. First, 7 ml of the first material is drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 80 μm and a pore size of 0.6 μm. Then, the spinning solution of the second material is quickly spun on the already formed film. 5 ml of the second material is drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 125 μm and a pore size of 0.60 μm. The prepared film is then repeatedly washed with ethanol solution and dried. The dried film is then immersed in PEI solution for 10 min and removed, and then dried for later use.

[0067] The composite nanofiber membrane has a pure water flux of 150,000 L·m -2 ·h -1 The bilirubin removal rate is ≥96.5%, and the large molecular oil rejection rate is ≥97.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high level of pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0068] Example 8

[0069] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.15 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0070] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0071] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: The first material consists of 8% base material, 5% TPU, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. PVP and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved. The second material consists of 8% base material, 5% TPU, 1% Cu / C-C3N5, 10% PVP, 0.5% CMC, and the remainder is N,N-dimethylformamide. Cu / C-C3N5, PVP, and CMC are dissolved in a solvent and heated with stirring. After dissolution, the base material and TPU are added, and heating and stirring continue for 1.5-3.5 hours until completely dissolved.

[0072] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 20 KV, the injection pump flow rate was 1.6 ml / h, and the receiving distance was 19 cm. The overall film-making process involved two materials being spun sequentially. First, 7 ml of the first material was drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 85 μm and a pore size of 0.7 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 6 ml of the second material was drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 120 μm and a pore size of 0.9 μm. The prepared film was then repeatedly washed with ethanol solution and dried. The dried film was then soaked in PEI solution for 10 min and then removed and dried for later use.

[0073] The composite nanofiber membrane has a pure water flux of 14000 L·m -2 ·h -1 The bilirubin removal rate is ≥89.5%, and the large molecular oil rejection rate is ≥95.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0074] Example 9

[0075] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.15 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0076] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0077] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 0.5% Cu / C-C3N5, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5, PVP, and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0078] Step 3) The spinning solution from step (2) is spun into a film using electrospinning. The DC voltage of the spinning machine is set to 20 KV, the injection pump flow rate is 1.4 ml / h, and the receiving distance is 20 cm. The overall film-making process involves two materials being spun sequentially. First, 7 ml of the first material is drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 70 μm and a pore size of 0.65 μm. Then, the spinning solution of the second material is quickly spun on the already formed film. 5 ml of the second material is drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 110 μm and a pore size of 0.7 μm. The prepared film is then repeatedly washed with ethanol solution and dried. The dried film is then soaked in PEI solution for 10 min and removed, and then dried for later use.

[0079] The composite nanofiber membrane has a pure water flux of 13500 L·m⁻¹ -2 ·h -1 The bilirubin removal rate is ≥86.5%, and the large molecular oil rejection rate is ≥98.9%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0080] Example 10

[0081] Step 1): Synthesis of Cu / C-C3N5: Weigh 1.0 g of 3-amino-1,2,4-triazole using an analytical balance and dissolve it in a 25 mL beaker. Measure 5 mL of distilled water into the beaker and dissolve it as well. Weigh 0.15 g of copper glycinate into the beaker. Place the beaker on a magnetic stirrer, cover the mouth with plastic wrap, and stir at room temperature for 3 hours. Then, place the sample in an oven (below 80℃) to completely dry it. Weigh the resulting solid sample, grind it in an agate mortar, and place it in a crucible. Heat the crucible in a muffle furnace to 550℃ at a heating rate of 5℃ / min. -1 The sample was kept at 550 ℃ for 3 h. After the reaction was completely cooled, the sample was taken out, ground, weighed, and loaded into a container. The resulting sample was labeled as Cu / C-C3N5.

[0082] After grinding in an agate mortar, the powder is placed in a crucible and then heated in a muffle furnace to 550 °C at a heating rate of 5 °C / min. -1 After holding the sample at 550 ℃ for 3 h and allowing it to cool completely, the sample is removed, ground, weighed, and loaded into a container to obtain Cu / C-C3N5.

[0083] Step 2): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 1.5% Cu / C-C3N5, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5, PVP, and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU, and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0084] Step 3) The spinning solution from step (2) is spun into a film using electrospinning. The DC voltage of the spinning machine is set to 20 KV, the injection pump flow rate is 1.4 ml / h, and the receiving distance is 20 cm. The overall film-making process involves two materials being spun sequentially. First, 7 ml of the first material is drawn in and spun for 4-6 h to form a nanofiber substrate film with a thickness of 75 μm and a pore size of 0.5 μm. Then, the spinning solution of the second material is quickly spun on the already formed film. 5 ml of the second material is drawn in and spun for 3-4 h to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 120 μm and a pore size of 0.7 μm. The prepared film is then repeatedly washed with ethanol solution and dried. The dried film is then soaked in PEI solution for 10 min and removed, and then dried for later use.

[0085] The composite nanofiber membrane has a pure water flux of 15000 L·m -2 ·h -1 The bilirubin removal rate is ≥92.4%, and the large molecular oil rejection rate is ≥98.5%, demonstrating significant effects in separating oil droplets and removing bilirubin. After undergoing a bilirubin removal cycle, the nanofiber membrane maintains a high pure water flux while exhibiting excellent bilirubin removal and oil rejection rates.

[0086] Example 11

[0087] Step 1): The spinning solution is prepared from two materials according to the following component mass percentages: First material: 10% base material, 5% TPU, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU and continue heating and stirring for 1.5-3.5 hours until completely dissolved. Second material: 10% base material, 5% TPU, 10% PVP, 0.5% CMC, with the remainder being N,N-dimethylformamide. Dissolve Cu / C-C3N5 PVP and CMC in a solvent and heat while stirring. After dissolving, add the base material and TPU and continue heating and stirring for 1.5-3.5 hours until completely dissolved.

[0088] Step 3) The spinning solution from step (2) was spun into a film using electrospinning. The DC voltage of the spinning machine was set to 20 KV, the injection pump flow rate was 1.4 ml / h, and the receiving distance was 20 cm. The overall film-making process involved two materials being spun sequentially. First, 7 ml of the first material was drawn in and spun for 4-6 hours to form a nanofiber substrate film with a thickness of 75 μm and a pore size of 0.5 μm. Then, the spinning solution of the second material was quickly spun on the already formed film. 5 ml of the second material was drawn in and spun for 3-4 hours to form a PVP, CMC-modified Cu / C-C3N5 nanofiber film with a total thickness of 120 μm and a pore size of 0.5 μm. The prepared film was then repeatedly washed with ethanol solution and dried.

[0089] The double-layer nanofiber membrane has a pure water flux of 12000 L·m -2 ·h -1 The bilirubin removal rate is ≥30.4%, and the macromolecular oil rejection rate is ≥94.5%. After undergoing the bilirubin removal cycle, the pure water flux decreases significantly.

Claims

1. A high-flux composite nanofiber membrane for bilirubin removal, characterized in that, Includes the following steps: (1) Synthesis of Cu / C-C3N5: A certain amount of nitrogen-containing organic matter was weighed using an analytical balance and dissolved in a beaker. An appropriate amount of distilled water was measured using a graduated cylinder and dissolved in the beaker. A certain amount of copper-containing carbon material was then weighed into the beaker. The beaker was placed on a magnetic stirrer, and the mouth of the beaker was covered with plastic wrap and stirred at room temperature for 3 hours. Then, the sample was placed in an oven at a temperature of less than 80°C to dry it completely. The obtained solid sample was weighed, ground in an agate mortar, and placed in a crucible. The crucible was then placed in a muffle furnace and heated to 550°C at a heating rate of 5°C / min. -1 The mixture is heated at 550 ℃ for 3 h. After the reaction has completely cooled, the sample is removed, ground, weighed, and loaded into containers to obtain Cu / C-C3N5. The nitrogen-containing organic compound is one or more of 3-amino-1,2,4-triazole, melamine, thiourea, dicyandiamide, and urea. The copper-containing carbon material is one or more of cuprous glycinate, copper glycinate, Prussian blue, and copper-carbon alloy nanoparticles. The copper-containing carbon material accounts for 0.5% to 5% of the total mass of the calcined material. (2) Preparation of spinning solution: The spinning solution is prepared by the first strand material and the second strand material according to the mass percentage of the components; the components of the first strand material are: 8-15% base material, 6-10% TPU, 1-10% polyvinylpyrrolidone, 0.5-1% carboxymethyl cellulose, and the remainder is N,N-dimethylformamide; the polyvinylpyrrolidone and carboxymethyl cellulose of the first strand material are dissolved in N,N-dimethylformamide and heated and stirred. After dissolving, the base material and TPU of the first strand material are added and heated and stirred for 1.5-3.5 h until completely dissolved; the components of the second strand material are: 11-15% base material, 4-10% TPU, Cu / C-C3N5 0.5-1.5%, polyvinylpyrrolidone 1-10%, carboxymethyl cellulose 0.5-1%, and the remainder is N,N-dimethylformamide; dissolve Cu / C-C3N5, polyvinylpyrrolidone and carboxymethyl cellulose of the second material in N,N-dimethylformamide and heat and stir. After dissolution, add the base material of the second material and TPU and continue heating and stirring for 1.5-3.5 h until completely dissolved; (3) Preparation of composite nanofiber membrane: The spinning solution in step (2) was spun into a membrane by electrospinning. The DC voltage of the spinning machine was set to 16-20 KV, the flow rate of the injection pump was 1.1-1.8 ml / h, and the receiving distance was 16-20 cm. The membrane preparation process involved two materials being spun continuously in sequence. First, 6-8 ml of the spinning solution of the first material was drawn in, and the nanofiber substrate was spun for 4-6 h to form a membrane with a thickness of 55-85 μm and a pore size of 0.5-1.5 μm. Then, the spinning solution of the second material was quickly spun on the membrane. 4-6 ml of the spinning solution of the second material was drawn in, and the nanofiber substrate was spun for 3-4 h to form a Cu / C-C3N5 nanofiber membrane modified with polyvinylpyrrolidone and carboxymethyl cellulose with a total thickness of 100-130 μm and a pore size of 0.5-1.5 μm. The prepared membrane was then repeatedly washed with ethanol solution and dried. The dried membrane was then soaked in PEI solution for 10 minutes, removed, and dried for later use.

2. The high-flux composite nanofiber membrane for bilirubin removal according to claim 1, characterized in that: In step (2), the substrate is one of polyvinylidene fluoride, polyethersulfone, polyacrylonitrile, polytetrafluoroethylene, polystyrene, cellulose and its derivatives.

3. A high-flux composite nanofiber membrane for bilirubin removal according to claim 1 or 2, characterized in that: The composite nanofiber membrane has a pure water flux of 13000-15000 L·m⁻¹ -2 ·h -1 The removal rate of bilirubin is ≥97.5%, and the retention rate of macromolecular oil is ≥99.5%.

4. An apparatus for bilirubin removal, characterized in that, The device is internally equipped with a high-throughput composite nanofiber membrane for bilirubin removal as described in any one of claims 1-3; according to the transport route of the bilirubin-containing oil-water mixture, the device includes: a bilirubin-containing oil-water mixture feed tank (1), a pump (2), a pressure gauge (3), a speed control gauge (4), a xenon lamp (5), a bilirubin-containing oil-water mixture separation device (6), an oil sludge storage tank (7), a valve (8), and a purified liquid storage tank (9).

5. The apparatus for bilirubin removal according to claim 4, characterized in that: The pump (2) is used to draw the bilirubin-containing oil-water mixture from the bilirubin-containing oil-water mixture feed tank (1), and after being adjusted by the pressure gauge (3) and the speed control gauge (4), it undergoes a photochemical reaction by being irradiated by the xenon lamp (5); then it is separated by the bilirubin-containing oil-water mixture separation device (6), the intercepted liquid enters the oil sludge storage tank (7), and the permeate flows into the closed bilirubin-containing oil-water mixture feed tank (1); the valve (8) is opened to collect the treated solution in the purified liquid storage tank (9).

6. An apparatus for bilirubin removal according to any one of claims 4-5, characterized in that: The oil-water mixture separation device (6) containing bilirubin can withstand a maximum pressure of 3 MPa; when the pump (2) transports the oil-water mixture containing bilirubin, the pressure should be lower than 3 MPa.

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