A method for constructing an antibiotic desalination nanofiltration membrane based on a doctor-blade assisted interfacial polymerization

Abstract

A method for constructing antibiotic desalination nanofiltration membrane based on doctor-blade assisted interfacial polymerization relates to the field of antibiotic desalination separation membrane. The COFs separation membrane is composed of a hydrolyzed polymer membrane support layer and a continuous COFs selective membrane; the COFs separation membrane is prepared by uniformly coating a hydrophobic ionic liquid solution containing COFs A monomers on a hydrolyzed polymer membrane rich in COFs B monomer aqueous solution by using a doctor blade, so that the COFs A and COFs B monomers perform Schiff base reaction between the ionic liquid-water interface; the COFs separation membrane has a uniform pore size distribution; the COFs separation membrane has pore size adjustability, the COFs separation membrane can be prepared in a short time (less than or equal to 2 min), and has good crystallization performance. The separation membrane can realize rapid and efficient separation of different antibiotic molecules and salts.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, and relates to antibiotic desalting separation membranes, and more particularly to a novel preparation method for a large-area defect-free COFs separation membrane. Background Technology

[0002] Antibiotics have played a vital role in social security and production in recent years due to their efficient, timely, simple, and economical action against pathogenic microorganisms. Currently, antibiotics are mainly produced in large quantities through fermentation processes, which include: seed fermentation, fermentation broth pretreatment, plate and frame filtration, ion exchange resin adsorption, ion exchange resin desorption, desalting, crystallization, and drying. To ensure the stability of the fermentation broth system, a certain amount of inorganic salt is usually added. Therefore, the separation of antibiotics and salts after fermentation is a necessary step. Traditional antibiotic desalting uses ion exchange resin adsorption, which is technically mature and stable; however, it suffers from problems such as cumbersome processes, complex equipment, and the use of large amounts of organic solvents. Membrane separation is a newly emerging antibiotic desalting technology in recent years, characterized by high efficiency and continuity, simple equipment, and no use of organic solvents, making it a green and efficient method for antibiotic desalting. Currently, membrane materials for membrane separation are mainly divided into polymer membranes with random pore structures and COFs separation membranes with regular pore structures. Polymer membrane materials, due to their dense structure and wide pore size distribution, often suffer from low water flux and poor antibiotic / salt selectivity in membrane-based antibiotic desalination. Covalently bonded layered crystalline polymers with long-range ordered structures and permanent porosity, unlike traditional polymers, possess uniform pore sizes that can be well controlled and adjusted through pre-monomer design. These advantages make COFs highly attractive for membrane separation applications. However, traditional synthesis methods, such as solvothermal synthesis, often produce insoluble microcrystalline COF powder, significantly limiting further applications. Therefore, converting powdered COFs into two-dimensional continuous COF membrane materials is crucial for practical applications. Currently, COF separation membranes are mainly prepared using liquid-liquid interfacial polymerization (LCIP). However, COF separation membranes prepared by LIP suffer from transfer difficulties, rendering them unusable directly. Furthermore, the size of the reaction vessel limits the large-area continuous production of COF separation membranes prepared by LIP. Preparing a COF selective layer on the polymer membrane surface through interfacial polymerization is a feasible method to address the aforementioned membrane transfer challenges; however, the resulting COF selective layer exhibits poor interfacial adhesion to the polymer membrane. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a new strategy for preparing a COFs separation membrane with a large area and uniform pore size, and to achieve the high efficiency of antibiotic desalting performance of the COFs separation membrane.

[0004] The first objective of this invention is to prepare large-area, continuous, defect-free COFs separation membranes using a novel strategy of blade coating-assisted interfacial polymerization, with the following steps:

[0005] S1. Place the polymer membrane in an aqueous NaOH solution (preferably 2.5M) and treat it at 60°C for 2 hours to obtain a hydrolyzed polymer membrane. Then, use deionized water to hydrolyze the polymer membrane to neutral pH.

[0006] S2. Immerse the hydrolyzed polymer membrane in an aqueous solution containing 0.5-2 wt% COFs B monomer and 0.05-0.15 wt% catalyst for 10 minutes. After removing it, use a pressure roller to remove excess aqueous solution from the surface, and then lay it flat on a film scraping machine.

[0007] S3. Pour the ionic liquid containing dissolved COFs A monomers onto the COFs B monomer-rich hydrolyzed polymer membrane obtained in S2. Then, under the action of a scraper, evenly coat the ionic liquid solution containing COFs A monomers onto the surface of the COFs B monomer-rich hydrolyzed polymer membrane obtained in S2.

[0008] S4. Allow the mixture to stand at room temperature for a period of time to allow COFs A monomers and COFs B monomers to undergo a Schiff base reaction at the ionic liquid-water interface to prepare a COFs separation membrane. The obtained COFs separation membrane can be prepared according to the required area, and the prepared COFs separation membrane has the properties of uniform pore size, good crystallinity, and membrane integrity.

[0009] In one embodiment, the polymer support layer includes polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose diacetate, cellulose triacetate, cyanoethyl cellulose acetate, polysulfone, polyethersulfone, sulfonated polysulfone, polysulfonamide, polyarylsulfone, polyvinylidene fluoride, and cellulose, and the polymer membrane is an ultrafiltration membrane with a pore size between 0.05 and 0.1 μm.

[0010] In one embodiment, the ionic liquid comprises one or more of trihexytetradecylphosphine bis(2,4,4-trimethylpentyl)hypophosphite and 1-butyl-3-methylimidazolium hexafluorophosphate.

[0011] In one embodiment, the COFs A monomer is selected from one or more of 1,3,5-tricarboxyloyl phloroglucinol, pyromellitic acid chloride, terephthalaldehyde, pyromellitic acid, and 2,4,6-trialdehyde-1,3,5-triazine.

[0012] In one embodiment, the COFs B monomer is selected from one or more of p-phenylenediamine, p-benzylenediamine, piperazine, 1,3,5-triaminobenzene, and 1,3,5-triazine-2,4,6-triamine.

[0013] In one embodiment, the mass ratio of the ionic liquid to COF A is 1 to 18:100.

[0014] In one embodiment, the mass ratio of water to COFs B monomer is 0.5 to 2:100.

[0015] The catalyst in step S2 is a conventional catalyst for the reaction of COF A and COFs B to generate COFs.

[0016] Regarding S4, the scraper speed, scraper height, and interface aggregation time include the following:

[0017] The effect of interfacial polymerization time on the microstructure of COFs separation membrane was investigated by controlling the scraper height within the range of 10–500 μm, the scraper speed within the range of 10–150 mm / s, and the interfacial polymerization time within the range of 1–30 min.

[0018] The thickness of COF selective films is 40–200 nm;

[0019] The COFs separation membrane obtained in this invention is used for the separation of antibiotics and salts.

[0020] The operating temperature is room temperature, and the operating pressure is 2-6 bar, achieving antibiotic / salt retention and separation.

[0021] The antibiotic is one of doxorubicin, tetracycline, chloramphenicol, norfloxacin, etc., and the concentration of the antibiotic is 10 mg / L to 200 mg / L; the salt is one or more of sodium sulfate, magnesium sulfate, sodium chloride, potassium chloride, etc., and the concentration of the salt is 0.5 g / L to 2 g / L.

[0022] Beneficial effects:

[0023] The present invention provides a rapid preparation method for large-area defect-free COFs separation membranes. Due to the selection of specific ionic liquids, considering the high viscosity, high solubility, hydrophobicity, and stable interface between ionic liquids and water, COFs separation membranes can be prepared continuously over a large area by a blade coating method.

[0024] The COFs separation membrane provided by this invention has strong design flexibility in the chain length and chain angle of its COFs monomers, which enables the preparation of COFs separation membranes with different pore sizes, thereby achieving rapid and accurate separation of antibiotic molecules and salts of different molecular sizes.

[0025] The COFs separation membrane provided by this invention, due to its uniform pore size distribution, utilizes the principle of pore size sieving to retain larger antibiotic molecules while allowing smaller salt molecules to pass through rapidly, achieving fast and precise separation of antibiotics and salts. The COFs separation membrane can be prepared in a short time (≤2 min) and exhibits good crystallization properties. Attached Figure Description

[0026] Figure 1 (a) Schematic diagram of COFs separation membrane preparation and (bd) COFs separation membranes with different pore sizes, i.e., separation membranes composed of different monomers.

[0027] Figure 2 The images show digital images of COFs separation membrane-1 corresponding to Example 1 of the present invention and COFs separation membranes prepared by unhydrolyzing polymer substrates according to Comparative Example 3 after water rinsing. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0029] The COFs separation membrane prepared in the following examples has an area of ​​425 cm². 2 The area could be further increased based on large-scale industrialization.

[0030] Example 1: Preparation of COFs Separation Membrane-1

[0031] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0032] The method for preparing the above-mentioned COFs separation membrane-1 includes the following steps:

[0033] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then wash the hydrolyzed polyacrylonitrile polymer membrane with deionized water until the pH is neutral.

[0034] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0035] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-1.

[0036] COFs separation membrane-1 antibiotic desalting performance test

[0037] COFs separation membrane-1 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0038] The retention rates of single-component antibiotics and salts by COFs separation membrane-1 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-1 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 97.8%, 98.9%, 64.7%, 94.7% and 17.2%, 14.5%, 11.5%, 10.8%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-1 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 48.19 L / m³. -2 h -1 bar -1 48.96L m -2 h -1 bar -1 48.97L m -2 h -1 bar -1 49.52L m -2 h - 1 bar -1 52.13L m -2 h -1 bar -1 52.23L m -2 h -1 bar -1 52.35L m -2 h -1 bar-1 53.24L m -2 h -1 bar -1 .

[0039] The retention capacity of COFs separation membrane-1 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-1 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 97.2% / 11.3%, 98.8% / 11.5%, 63.8% / 11.4%, and 95.2% / 11.6%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-1 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 48.07 L / m³. -2 h -1 bar -1 48.19L m -2 h -1 bar -1 48.45L m -2 h -1 bar -1 49.07L m -2 h -1 bar -1 .

[0040] Example 2: Preparation of COFs separation membrane-2

[0041] In this embodiment, the ionic liquid used is 1-butyl-3-methylimidazolium hexafluorophosphate, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0042] The method for preparing the above-mentioned COFs separation membrane-2 includes the following steps:

[0043] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then wash the hydrolyzed polyacrylonitrile polymer membrane with deionized water until the pH is neutral.

[0044] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0045] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polymer rich in COFs B monomer aqueous solution. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polyacrylonitrile polymer film rich in COFs B monomer aqueous solution under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-2.

[0046] COFs separation membrane-2 antibiotic desalting performance test

[0047] COFs separation membrane-2 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0048] The retention rates of single-component antibiotics and salts by COFs separation membrane-2 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-2 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 87.8%, 85.2%, 40.1%, 82.6% and 12.2%, 12.1%, 9.8%, 7.2%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-2 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 52.30 L / m³. -2 h -1 bar -1 52.56L m -2 h -1 bar -1 52.98L m -2 h -1 bar -1 53.21L m -2 h - 1 bar -1 54.30L m -2 h -1 bar-1 54.63L m -2 h -1 bar -1 54.75L m -2 h -1 bar -1 55.21L m -2 h -1 bar -1 .

[0049] The retention capacity of COFs separation membrane-2 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-2 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 86.2% / 9.6%, 84.2% / 9.5%, 43.2% / 9.6%, and 83.6% / 9.6%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-2 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 52.02 L / m³. -2 h -1 bar -1 52.11L m -2 h -1 bar -1 52.18L m -2 h -1 bar -1 53.20Lm -2 h -1 bar -1 .

[0050] Example 3: Preparation of COFs Separation Membrane-3

[0051] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyethersulfone, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0052] The method for preparing the above-mentioned COFs separation membrane-3 includes the following steps:

[0053] S1. Place the polyethersulfone polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyethersulfone polymer membrane. Then, use deionized water to hydrolyze the polyethersulfone polymer membrane to neutral pH.

[0054] S2. Soak the hydrolyzed polyethersulfone polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0055] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyethersulfone polymer rich in COFs B monomer aqueous solution. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in COFs B monomer aqueous solution under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-3.

[0056] COFs separation membrane-3 antibiotic desalting performance test

[0057] COFs separation membrane-3 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0058] The retention rates of single-component antibiotics and salts by COFs separation membrane-3 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-3 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 98.5%, 97.2%, 75.6%, 93.6% and 12.6%, 12.3%, 10.8%, 10.5%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-3 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 48.65 L / m³. -2 h -1 bar -1 48.95L m -2 h -1 bar -1 49.18L m -2 h -1 bar -1 50.21L m-2 h - 1 bar -1 53.65L m -2 h -1 bar -1 53.78L m -2 h -1 bar -1 53.82L m -2 h -1 bar -1 53.98L m -2 h -1 bar -1 .

[0059] The retention capacity of COFs separation membrane-3 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-3 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 98.6% / 10.9%, 97.4% / 10.9%, 75.6% / 10.9%, and 92.9% / 11.0%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-3 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 48.24 L / m³. -2 h -1 bar -1 48.31L m -2 h -1 bar -1 48.48L m -2 h -1 bar -1 48.67L m -2 h -1 bar -1 .

[0060] Example 4: Preparation of COFs Separation Membrane-4

[0061] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0062] The method for preparing the above-mentioned COFs separation membrane-4 includes the following steps:

[0063] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0064] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0065] S3. Pour the ionic liquid solution containing 2 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 2 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-4.

[0066] COFs separation membrane-4 antibiotic desalting performance test

[0067] COFs separation membrane-4 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0068] The retention rates of single-component antibiotics and salts by COFs separation membrane-4 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-4 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 89.6%, 87.8%, 60.5%, 85.5% and 11.2%, 10.2%, 10.0%, 9.3%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-4 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 51.52 L / m³. -2 h -1 bar -1 51.65L m -2 h -1 bar -1 51.72L m -2 h-1 bar -1 51.88L m -2 h - 1 bar -1 53.98.30L m -2 h -1 bar -1 54.25L m -2 h -1 bar -1 54.28L m -2 h -1 bar -1 54.66L m -2 h -1 bar -1 .

[0069] The retention capacity of COFs separation membrane-4 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-4 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 88.9% / 10.2%, 88.6% / 10.1%, 61.5% / 10.4%, and 85.7% / 10.2%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-4 for these mixed solutions in the mixed system was 50.96 L / m³. -2 h -1 bar -1 51.13L m -2 h -1 bar -1 51.24L m -2 h -1 bar -1 51.46L m -2 h -1 bar -1 .

[0070] Example 5: Preparation of COFs Separation Membrane-5

[0071] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0072] The method for preparing the above-mentioned COFs separation membrane-5 includes the following steps:

[0073] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then wash the hydrolyzed polyacrylonitrile polymer membrane with deionized water until the pH is neutral.

[0074] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0075] S3. Pour the ionic liquid solution containing 8 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 8 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-5.

[0076] COFs separation membrane-5 antibiotic desalting performance test

[0077] COFs separation membrane-5 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0078] The retention rates of single-component antibiotics and salts by COFs separation membrane-5 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-5 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 98.6%, 97.8%, 66.3%, 95.6% and 13.2%, 12.2%, 11.9%, 10.3%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-5 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 47.25 L / m³. -2 h -1 bar -1 47.53L m -2 h -1 bar-1 47.65L m -2 h -1 bar -1 47.98L m -2 h - 1 bar -1 49.65L m -2 h -1 bar -1 49.89L m -2 h -1 bar -1 50.36L m -2 h -1 bar -1 51.36L m -2 h -1 bar -1 .

[0079] The retention capacity of COFs separation membrane-5 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and sodium chloride retention was monitored using a conductivity meter. The results showed that in single systems, the retention rates of COFs separation membrane-5 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride were 98.5% / 10.9%, 97.9% / 10.9%, 65.9% / 11.0%, and 95.3% / 11.2%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-5 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed systems was 46.85 L / m³. -2 h -1 bar -1 46.95L m -2 h -1 bar -1 47.14L m -2 h - 1 bar -1 47.28L m -2 h -1 bar -1 .

[0080] Example 6: Preparation of COFs Separation Membrane-6

[0081] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0082] The method for preparing the above-mentioned COFs separation membrane-6 includes the following steps:

[0083] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0084] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0085] S3. Pour the ionic liquid solution containing 16 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 16 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-6.

[0086] COFs separation membrane-6 antibiotic desalination performance test

[0087] COFs separation membrane-6 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0088] The retention rates of single-component antibiotics and salts by COFs separation membrane-6 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single-component systems, the retention rates of COFs separation membrane-6 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 98.7%, 98.5%, 78.5%, 97.9% and 16.3%, 15.7%, 15.2%, 11.9%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-6 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single-component systems was 45.65 L / m³. -2 h -1 bar -1 45.98L m -2 h -1 bar -1 46.52L m -2 h -1 bar -1 46.98L m -2 h - 1 bar -1 48.02L m -2 h -1 bar -1 48.32L m -2 h -1 bar -1 48.87L m -2 h -1 bar -1 48.95L m -2 h -1 bar -1 .

[0089] The retention capacity of COFs separation membrane-6 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-6 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 97.9% / 15.3%, 97.6% / 15.3%, 77.9% / 15.2%, and 96.8% / 15.4%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-6 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 45.14 L / m³. -2 h -1 bar -1 45.21L m -2 h -1 bar -1 46.29L m -2 h -1 bar -1 46.37L m -2 h -1 bar -1 .

[0090] Example 7: Preparation of COFs Separation Membrane-7

[0091] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0092] The method for preparing the above-mentioned COFs separation membrane-7 includes the following steps:

[0093] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0094] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0095] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 25 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-7.

[0096] COFs separation membrane-7 antibiotic desalting performance test

[0097] The COFs separation membrane-7 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0098] The retention rates of single-component antibiotics and salts by COFs separation membrane-7 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-7 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 90.1%, 87.5%, 59.8%, 86.8% and 11.3%, 10.4%, 9.5%, 8.8%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-7 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 48.65 L / m³. -2 h -1 bar -1 48.98L m -2 h -1 bar -1 49.65L m -2 h -1 bar -1 50.32Lm -2 h -1 bar -1 53.20L m -2 h -1 bar -1 53.42L m -2 h -1 bar -1 53.65L m -2 h -1 bar -1 53.74L m-2 h -1 bar -1 .

[0099] The retention capacity of COFs separation membrane-7 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-7 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 90.5% / 9.4%, 88.1% / 9.3%, 60.1% / 9.3%, and 86.9% / 9.3%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-7 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 47.89 L / m³. -2 h -1 bar -1 48.07L m -2 h -1 bar -1 48.19L m -2 h -1 bar -1 48.52Lm -2 h -1 bar -1 .

[0100] Example 8: Preparation of COFs Separation Membrane-8

[0101] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0102] The method for preparing the above-mentioned COFs separation membrane-8 includes the following steps:

[0103] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0104] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0105] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in COFs B monomer aqueous solution. Adjust the scraper height to 250 μm and the scraper speed to 50 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in COFs B monomer aqueous solution under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-8.

[0106] COFs separation membrane-8 antibiotic desalination performance test

[0107] COFs separation membrane-8 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0108] The retention rates of single-component antibiotics and salts by COFs separation membrane-8 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-8 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 97.5%, 97.1%, 60.3%, 94.2% and 16.9%, 16.5%, 13.5%, 12.7%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-8 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 47.92 L / m³. -2 h -1 bar -1 48.24L m -2 h -1 bar -1 48.29L m -2 h -1 bar -1 48.52L m -2 h -1 bar -1 52.32L m -2 h -1 bar -1 52.46L m -2 h -1 bar -1 52.78L m -2 h -1 bar -153.01L m -2 h -1 bar -1 .

[0109] The retention capacity of COFs separation membrane-8 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-8 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed systems were 97.9% / 13.2%, 96.8% / 12.8%, 59.4% / 12.9%, and 94.6% / 13.2%, respectively. The flux of COFs separation membrane-8 for these mixed solutions in the mixed systems was 47.24 L / m³. -2 h -1 bar -1 47.45L m -2 h -1 bar -1 47.85L m -2 h -1 bar -1 47.95L m -2 h -1 bar -1 .

[0110] Example 9: Preparation of COFs Separation Membrane-9

[0111] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0112] The method for preparing the above-mentioned COFs separation membrane-9 includes the following steps:

[0113] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0114] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0115] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 100 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-9.

[0116] COFs separation membrane-9 antibiotic desalting performance test

[0117] The COFs separation membrane-9 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0118] The retention rates of single-component antibiotics and salts by COFs separation membrane-9 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-9 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 89.6%, 88.8%, 57.1%, 87.6% and 11.2%, 10.7%, 9.7%, 9.3%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-9 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 52.30 L / m³. -2 h -1 bar -1 52.42L m -2 h -1 bar -1 52.62L m -2 h -1 bar -1 53.01L m -2 h - 1 bar -1 54.25L m -2 h -1 bar -1 54.62L m -2 h -1 bar -1 54.84L m -2 h-1 bar -1 54.94L m -2 h -1 bar -1 .

[0119] The retention capacity of COFs separation membrane-9 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-9 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 89.1% / 10.2%, 88.4% / 10.0%, 56.8% / 10.8%, 84.2%, and 9.9%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-9 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 52.10 L / m³. -2 h -1 bar -1 52.16L m -2 h -1 bar -1 52.33L m -2 h -1 bar -1 52.65L m -2 h -1 bar -1 .

[0120] Example 10: Preparation of COFs Separation Membrane-10

[0121] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0122] The method for preparing the above-mentioned COFs separation membrane-10 includes the following steps:

[0123] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0124] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0125] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 100 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-10.

[0126] COFs separation membrane-10 antibiotic desalination performance test

[0127] The COFs separation membrane-10 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0128] The retention rates of single-component antibiotics and salts by COFs separation membrane-10 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-10 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 95.1%, 94.5%, 62.5%, 93.9% and 16.8%, 13.3%, 12.7%, 11.8%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-10 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 49.52 L / m³. -2 h -1 bar -1 49.65L m -2 h -1 bar -1 50.21L m -2 h -1 bar -1 50.65L m -2 h -1 bar -1 53.42L m -2 h -1 bar -153.82L m -2 h -1 bar -1 53.95L m -2 h -1 bar -1 54.01L m - 2 h -1 bar -1 .

[0129] The retention capacity of COFs separation membrane-10 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-10 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 95.1% / 12.9%, 94.2% / 13.2%, 62.3% / 12.9%, 93.5%, and 13.1%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-10 for these mixed solutions in the mixed system was 48.85 L / m³. -2 h -1 bar -1 48.96L m -2 h -1 bar -1 49.11L m -2 h - 1 bar -1 49.51L m -2 h -1 bar -1 .

[0130] Example 11 Preparation of COFs separation membrane-11

[0131] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0132] The method for preparing the above-mentioned COFs separation membrane-11 includes the following steps:

[0133] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0134] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0135] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 300 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-11.

[0136] COFs separation membrane-11 antibiotic desalting performance test

[0137] The COFs separation membrane-11 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0138] The retention rates of single-component antibiotics and salts by the COFs separation membrane-11 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the COFs separation membrane-11 retained 98.2%, 97.9%, 64.5%, and 96.8% of doxorubicin, tetracycline, chloramphenicol, and norfloxacin, and 18.2%, 17.3%, 14.6%, and 13.8% of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively. Following the pore size sieving principle, the flux of the COFs separation membrane-11 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and the aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 48.20 L / m³. -2 h -1 bar -1 48.32L m -2 h -1 bar -1 48.41L m -2 h -1 bar -148.52L m -2 h -1 bar -1 49.50L m -2 h -1 bar -1 49.67L m -2 h -1 bar -1 49.82L m -2 h -1 bar -1 50.14L m - 2 h -1 bar -1 .

[0139] The retention capacity of COFs separation membrane-11 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-11 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 98.4% / 14.9%, 97.5% / 14.8%, 63.9% / 15.0%, and 96.2% / 15.1%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-11 for these mixed solutions in the mixed system was 47.65 L / m³. -2 h -1 bar -1 47.84L m -2 h -1 bar -1 48.01L m -2 h - 1 bar -1 48.09L m -2 h -1 bar -1 .

[0140] Example 12 Preparation of COFs Separation Membrane-12

[0141] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0142] The method for preparing the above-mentioned COFs separation membrane-12 includes the following steps:

[0143] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0144] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0145] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 500 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-12.

[0146] COFs separation membrane-12 antibiotic desalting performance test

[0147] The COFs separation membrane-12 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0148] The retention rates of single-component antibiotics and salts by COFs separation membrane-12 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-12 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 98.8%, 98.6%, 70.3%, 98.5% and 23.1%, 19.5%, 17.6%, 16.5%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-12 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 46.21 L / m³. -2 h -1 bar -1 46.34L m -2 h -1 bar -146.52L m -2 h -1 bar -1 46.61L m -2 h -1 bar -1 47.50L m -2 h -1 bar -1 47.60L m -2 h -1 bar -1 47.78L m -2 h -1 bar -1 47.84L m - 2 h -1 bar -1 .

[0149] The retention capacity of COFs separation membrane-12 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-12 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 98.8% / 12.5%, 98.3% / 12.3%, 68.9% / 12.5%, and 98.6% / 12.6%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-12 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 46.07 L / m³. -2 h -1 bar -1 46.18L m -2 h -1 bar -1 46.31L m -2 h - 1 bar -1 46.41L m -2 h -1 bar -1 .

[0150] Example 13 Preparation of COFs Separation Membrane-13

[0151] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0152] The method for preparing the above-mentioned COFs separation membrane-13 includes the following steps:

[0153] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0154] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0155] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 1 min to obtain COFs separation membrane-13.

[0156] COFs separation membrane-13 antibiotic desalting performance test

[0157] COFs separation membrane-13 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0158] The retention rates of single-component antibiotics and salts by COFs separation membrane-13 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-13 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 88.6%, 85.6%, 51.3%, 84.2% and 11.5%, 10.6%, 10.2%, 9.7%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-13 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 51.53 L / m³. -2 h -1 bar -1 52.06L m -2 h -1 bar -1 52.31L m -2 h -1 bar -1 52.61L m -2 h -1 bar -1 55.01L m -2 h -1 bar -1 55.30L m -2 h -1 bar -1 55.67L m -2 h -1 bar -1 55.84L m - 2 h -1 bar -1 .

[0159] The retention capacity of COFs separation membrane-13 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-13 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system were 87.9% / 8.6%, 85.4% / 8.8%, 49.8% / 8.7%, and 83.1% / 8.6%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-13 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 51.24 L / m³. -2 h -1 bar -1 51.31L m -2 h -1 bar -1 51.71L m -2 h -1 bar -1 52.10L m -2 h -1 bar -1 .

[0160] Example 14 Preparation of COFs Separation Membrane-14

[0161] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0162] The method for preparing the above-mentioned COFs separation membrane-14 includes the following steps:

[0163] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0164] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0165] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 10 min to obtain COFs separation membrane-14.

[0166] COFs separation membrane-14 antibiotic desalting performance test

[0167] COFs separation membrane-14 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0168] The retention rates of single-component antibiotics and salts by COFs separation membrane-14 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-14 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 98.6%, 98.1%, 66.8%, 97.5% and 18.9%, 17.5%, 16.8%, 15.4%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-14 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 47.01 L / m³. -2 h -1 bar -1 47.17L m -2 h -1 bar -1 47.31L m -2 h -1 bar -1 47.35L m -2 h -1 bar -1 48.65L m -2 h -1 bar -1 48.75L m -2 h -1 bar -1 48.93L m -2 h -1 bar -149.02L m - 2 h -1 bar -1 .

[0169] The retention capacity of COFs separation membrane-14 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of COFs separation membrane-14 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 98.4% / 11.5%, 97.6% / 11.8%, 65.8% / 11.9%, and 97.5% / 11.8%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-14 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed system was 46.50 L / m³. -2 h -1 bar -1 46.74L m -2 h -1 bar -1 46.88L m -2 h - 1 bar -1 47.22L m -2 h -1 bar -1 .

[0170] Example 15 Preparation of COFs Separation Membrane-15

[0171] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0172] The method for preparing the above-mentioned COFs separation membrane-15 includes the following steps:

[0173] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0174] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0175] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 30 min to obtain COFs separation membrane-15.

[0176] COFs separation membrane-15 antibiotic desalting performance test

[0177] The COFs separation membrane-15 was installed in a cross-flow separation device for antibiotic desalting tests at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0178] The retention rates of single-component antibiotics and salts by the COFs separation membrane-15 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the COFs separation membrane-15 exhibited retention rates of 99.3%, 98.8%, 70.6%, 98.5% for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and 23.4%, 21.8%, 18.6%, 17.6% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively. Following the pore size sieving principle, the flux of the COFs separation membrane-15 in the single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and the aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 43.21 L / m³. -2 h -1 bar -1 43.60L m -2 h -1 bar -1 43.71L m -2 h -1 bar -1 43.78L m - 2 h -1 bar -1 44.72L m -2 h -1 bar-1 44.80L m -2 h -1 bar -1 44.93L m -2 h -1 bar -1 44.97L m -2 h -1 bar -1 .

[0179] The retention capacity of COFs separation membrane-15 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in single systems, the retention rates of COFs separation membrane-15 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride were 99.5% / 17.8%, 99.2% / 17.7%, 71.6% / 17.5%, and 98.2% / 18.0%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-15 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed systems was 41.20 L / m³. -2 h -1 bar -1 41.35L m -2 h -1 bar -1 41.52L m -2 h - 1 bar -1 41.85L m -2 h -1 bar -1 .

[0180] Example 16 Preparation of COFs Separation Membrane-16

[0181] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is hydrazine, and the catalyst is p-toluenesulfonic acid.

[0182] The method for preparing the above-mentioned COFs separation membrane-16 includes the following steps:

[0183] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0184] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0185] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-16.

[0186] COFs separation membrane-16 antibiotic desalting performance test

[0187] The COFs separation membrane-16 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0188] The retention rates of single-component antibiotics and salts by COFs separation membrane-16 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-16 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 99.5%, 99.2%, 81.6%, 98.9% and 25.5%, 23.5%, 19.5%, 18.4%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-16 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 44.21 L / m³. -2 h -1 bar -1 44.32L m -2 h -1 bar -1 44.40L m -2 h -1 bar -144.52L m - 2 h -1 bar -1 46.30L m -2 h -1 bar -1 46.52L m -2 h -1 bar -1 46.63L m -2 h -1 bar -1 46.89L m -2 h -1 bar -1 .

[0189] The retention capacity of COFs separation membrane-16 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in single systems, the retention rates of COFs separation membrane-16 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride were 99.8% / 19.6%, 99.5% / 19.7%, 81.7% / 20.1%, and 99.2% / 19.9%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-16 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed systems was 43.58 L / m³. -2 h -1 bar -1 43.71L m -2 h -1 bar -1 43.86L m -2 h - 1 bar -1 44.11L m -2 h -1 bar -1 .

[0190] Example 17 Preparation of COFs Separation Membrane-17

[0191] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is 4,4'-diaminobiphenyl, and the catalyst is p-toluenesulfonic acid.

[0192] The method for preparing the above-mentioned COFs separation membrane-17 includes the following steps:

[0193] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then, use deionized water to hydrolyze the polyacrylonitrile polymer membrane to neutral pH.

[0194] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0195] S3. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain COFs separation membrane-17.

[0196] COFs separation membrane-17 antibiotic desalting performance test

[0197] COFs separation membrane-17 was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0198] The retention rates of single-component antibiotics and salts by COFs separation membrane-17 were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single system, the retention rates of COFs separation membrane-17 for doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 95.5%, 94.8%, 69.5%, 93.5% and 16.2%, 15.8%, 12.3%, 11.1%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-17 for aqueous solutions of doxorubicin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride in the single system was 47.82 L / m³. -2 h -1 bar -1 47.95L m -2 h -1 bar-1 48.21L m -2 h -1 bar -1 48.50L m - 2 h -1 bar -1 47.65L m -2 h -1 bar -1 47.81L m -2 h -1 bar -1 47.89L m -2 h -1 bar -1 47.97L m -2 h -1 bar -1 .

[0199] The retention capacity of COFs separation membrane-17 for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in single systems, the retention rates of COFs separation membrane-17 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride were 94.8% / 12.3%, 93.2% / 12.2%, 69.2% / 12.1%, and 92.8% / 12.3%, respectively. Following the pore size sieving principle, the flux of COFs separation membrane-17 for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride mixed solutions in the mixed systems was 47.04 L / m³. -2 h -1 bar -1 47.11L m -2 h -1 bar -1 47.42L m -2 h - 1 bar -1 47.54L m -2 h -1 bar -1 .

[0200] Comparative Example 1: Comparison of COFs separation membrane area prepared by conventional interfacial polymerization method with that prepared by blade-coated assisted interfacial polymerization method.

[0201] In this comparative example, the COFs A monomer used was 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer was p-phenylenediamine, the COFs A monomer solvent was dichloromethane, the COFs B monomer solvent was water, and the catalyst was p-toluenesulfonic acid.

[0202] The method for preparing the above-mentioned COFs separation membrane includes the following specific steps:

[0203] S1. Pour 50 mL of dichloromethane solution containing 4 wt% COFs A monomer into a beaker with a diameter of 6 cm and a volume of 250 mL.

[0204] S2. Pour 50 mL of an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid into the beaker containing the dichloromethane solution described in S1.

[0205] S3. Let stand at room temperature for 2 minutes to form a COFs separation membrane at the dichloromethane-water interface.

[0206] The COFs separation membrane has an area of ​​28.26 cm². 2 However, under the influence of external forces, the membrane structure cannot maintain its integrity, and it is challenging to directly transfer it to membrane devices that cannot be directly transferred for antibiotic desalination applications.

[0207] Compared with Comparative Example 1, it was found that the COFs separation membrane prepared by the traditional liquid-liquid interface polymerization method has a small area and is difficult to transfer, so it cannot be directly applied in the field of antibiotic desalting.

[0208] Comparative Example 2: Effect of COFs separation membranes prepared using 1-butyl-3-methylimidazolium chloride ionic liquid on their antibiotic desalting performance.

[0209] In this embodiment, the ionic liquid used is 1-butyl-3-methylimidazolium chloride, the polymer membrane is hydrolyzed polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0210] The method for preparing the above-mentioned COFs separation membrane is characterized by comprising the following specific steps:

[0211] S1. Place the polyacrylonitrile polymer membrane in a 2.5M / L NaOH aqueous solution and treat it at 60℃ for 2h to obtain a hydrolyzed polyacrylonitrile polymer membrane. Then wash the hydrolyzed polyacrylonitrile polymer membrane with deionized water until the pH is neutral.

[0212] S2. Soak the hydrolyzed polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 min. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0213] S3. Pour a 1-butyl-3-methylimidazolium chloride ionic liquid solution containing 4 wt% COFs A monomer onto the surface of a hydrolyzed polyacrylonitrile polymer rich in an aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in an aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain a COFs separation membrane.

[0214] The COFs separation membrane was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0215] The retention rates of the COFs separation membrane for single-component antibiotics and salts were investigated. The aqueous solutions of antibiotics and salts were at concentrations of 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in a single system, the COFs separation membrane exhibited retention rates of 32.2% for doxorubicin, 29.6% for tetracycline, 20.3% for chloramphenicol, 27.8% for norfloxacin, 6.7% for sodium sulfate, 6.1% for magnesium sulfate, 4.6% for sodium chloride, and 4.3% for potassium chloride. The flux of the COFs separation membrane in a single system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 382.42 Lm³. -2 h -1 bar -1 382.42L m -2 h -1 bar -1 382.50L m -2 h -1 bar -1 382.50L m -2 h -1 bar -1 382.50L m -2 h - 1 bar -1 382.50L m -2 h -1 bar-1 382.61L m -2 h -1 bar -1 382.61L m -2 h -1 bar -1 .

[0216] The retention capacity of the COFs separation membrane for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of the COFs separation membrane for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 31.5% / 4.7%, 28.7% / 4.8%, 27.2% / 4.8%, and 27.2% / 4.9%, respectively. The flux of the COFs separation membrane for these mixed solutions was 382.41 L / m³. -2 h -1 bar -1 382.41L m -2 h -1 bar -1 382.41L m -2 h -1 bar -1 382.41L m - 2 h -1 bar -1 .

[0217] A comparison with Comparative Example 2 revealed that the 1-butyl-3-methylimidazolium chloride ionic liquid used prevented the formation of a stable interface between the ionic liquid and water during the preparation process, thus failing to produce a continuous COF separation membrane and resulting in a sharp decrease in its antibiotic desalination performance.

[0218] Comparative Example 3: Effect of Unhydrolyzed Polymer Membrane on Antibiotic Desalination Performance of COF Separation Membrane

[0219] In this embodiment, the ionic liquid used is trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite, the polymer membrane is polyacrylonitrile, the COFs A monomer is 1,3,5-tricarboxymethyl phloroglucinol, the COFs B monomer is p-phenylenediamine, and the catalyst is p-toluenesulfonic acid.

[0220] The method for preparing the above-mentioned COFs separation membrane is characterized by comprising the following specific steps:

[0221] S1. Immerse the polyacrylonitrile polymer film in an aqueous solution containing 1 wt% COFs B monomer and 1 wt% p-toluenesulfonic acid for 10 minutes. After taking it out, remove the excess aqueous solution from the surface with a pressure roller and then lay it flat on a film scraper.

[0222] S2. Pour the ionic liquid solution containing 4 wt% COFs A monomer onto the surface of the hydrolyzed polyacrylonitrile polymer rich in the aqueous solution of COFs B monomer. Adjust the scraper height to 250 μm and the scraper speed to 75 mm / s, so that the ionic liquid solution containing 4 wt% COFs A monomer is evenly coated on the hydrolyzed polymer film rich in the aqueous solution of COFs B monomer under the action of the scraper. Then let it stand at room temperature for 2 min to obtain the COFs separation membrane.

[0223] The COFs separation membrane was installed in a cross-flow separation device for antibiotic desalting testing at room temperature, with an operating pressure of 2–6 bar. The selected antibiotic molecules and salts were doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0224] The retention rates of the COFs separation membrane for single-component antibiotics and salts were investigated. The aqueous solutions of antibiotics and salts were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the single-system, the COFs separation membrane exhibited retention rates of 37.1%, 35.2%, 256%, 34.8%, 6.8%, 6.3%, 4.6%, and 4.2% for doxorubicin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively. The flux of the COFs separation membrane in the single-system for doxorubicin, tetracycline, chloramphenicol, norfloxacin, and aqueous solutions of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride was 354.26 Lm. -2 h -1 bar -1 384.26L m -2 h -1 bar -1 354.26L m -2 h -1 bar -1 354.26L m -2 h -1 bar -1 354.30L m -2 h - 1 bar -1 354.31L m -2 h-1 bar -1 354.32L m -2 h -1 bar -1 354.42L m -2 h -1 bar -1 .

[0225] The retention capacity of the COFs separation membrane for antibiotic / sodium chloride mixed solutions was investigated. The concentrations of antibiotic and sodium chloride in the mixed aqueous solution were 100 mg / L and 1 g / L, respectively. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that the retention rates of the COFs separation membrane for doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 36.6% / 5.0%, 35.6% / 4.9%, 25.6% / 4.9%, and 34.8% / 5.0%, respectively. The flux of the COFs separation membrane for the mixed solutions of doxorubicin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system was 354.27 L / m³. -2 h -1 bar -1 384.27L m -2 h -1 bar -1 354.27L m -2 h -1 bar -1 354.28L m - 2 h -1 bar -1 .

[0226] Comparison with Comparative Example 3 revealed that the unhydrolyzed polyacrylonitrile membrane lacked a strong bond between the COFs membrane selective layer and the polymer membrane substrate. This resulted in the COFs membrane selective layer easily detaching during antibiotic desalination applications, ultimately rendering it unusable. Figure 2 ).

Claims

1. A method for constructing antibiotic desalination nanofiltration membranes based on a coating-assisted interfacial polymerization method, characterized in that, Includes the following steps: S1. Place the polymer film in an aqueous NaOH solution and heat it at 60°C. o After treatment at C for 2 h, a hydrolyzed polymer membrane was obtained. The membrane was then washed with deionized water until it reached pH neutral. S2. Immerse the hydrolyzed polymer membrane in an aqueous solution containing 0.5-2 wt% COFs B monomer and 0.05-0.15 wt% catalyst for 10 min. After removing it, use a pressure roller to remove excess aqueous solution from the surface, and then lay it flat on a film scraper. S3. Pour the ionic liquid containing dissolved COFs A monomers onto the COFs B monomer-rich hydrolyzed polymer membrane obtained in S2. Then, under the action of a scraper, evenly coat the ionic liquid solution containing COFs A monomers onto the surface of the COFs B monomer-rich hydrolyzed polymer membrane obtained in S2. S4. Allow the COFs A monomer and COFs B monomer to stand at room temperature for a period of time, and then perform a Schiff base reaction at the ionic liquid-water interface to prepare a COFs separation membrane. The obtained COFs separation membrane can be prepared according to the required area. The prepared COFs separation membrane has the properties of uniform pore size, good crystallinity and membrane integrity. The ionic liquid comprises one or more of trihexyltetradecylphosphine bis(2,4,4-trimethylpentyl) hypophosphite and 1-butyl-3-methylimidazolium hexafluorophosphate; The COFs A monomer is selected from one or more of 1,3,5-tricarboxyloyl phloroglucinol, pyromellitic acid chloride, terephthalaldehyde, pyromellitic acid, and 2,4,6-trialdehyde-1,3,5-triazine; the mass ratio of the ionic liquid to COFs A is 1~18:

100. The COFs B monomer is selected from one or more of p-phenylenediamine, p-benzylenediamine, piperazine, 1,3,5-triaminobenzene, and 1,3,5-triazine-2,4,6-triamine; Regarding S4, the scraper speed, scraper height, and interface aggregation time include the following: The influence of interfacial polymerization time on the microstructure of COFs separation membrane was investigated by controlling the scraper height within the range of 10 to 500 μm, the scraper speed within the range of 10 to 150 mm / s, and the interfacial polymerization time within the range of 1 to 30 min. The thickness of the COF separation membrane is 40~200 nm.

2. The method for constructing an antibiotic desalination nanofiltration membrane based on a coating-assisted interfacial polymerization method according to claim 1, characterized in that, The polymer membrane is selected from one of polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose diacetate, cellulose triacetate, cyanoethyl cellulose acetate, polysulfone, polyethersulfone, sulfonated polysulfone, polysulfonamide, polyarylsulfone, polyvinylidene fluoride, and cellulose, and the polymer membrane is an ultrafiltration membrane with a pore size between 0.05 and 0.1 μm.

3. The method for constructing an antibiotic desalination nanofiltration membrane based on a coating-assisted interfacial polymerization method according to claim 1, characterized in that, The mass ratio of water to COFs B monomer is 0.5~2:

100.

4. The antibiotic desalination nanofiltration membrane prepared by the method according to any one of claims 1-3 based on the coating-assisted interfacial polymerization.

5. The application of the antibiotic desalination nanofiltration membrane prepared by the method according to any one of claims 1-3, for the separation of antibiotics and salts.

6. The application according to claim 5, wherein the operating temperature is room temperature and the operating pressure is 2-6 bar, achieves antibiotic / salt retention separation; The antibiotic is one of doxorubicin, tetracycline, chloramphenicol, and norfloxacin, and the concentration of the antibiotic is 10 mg / L to 200 mg / L; the salt is one or more of sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, and the concentration of the salt is 0.5 g / L to 2 g / L.

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