Desalination separation membrane, method for preparing the same, and use thereof

Abstract

This invention discloses a desalination membrane, its preparation method, and its application, relating to the field of chemical separation technology. It provides a novel strategy for preparing a new antibiotic desalination membrane based on an interfacial polymerization process controlled by amino-rich monomers. The separation membrane is composed of a polymer membrane support layer and a continuous polyamide selective layer. The polymer membrane is an ultrafiltration membrane with a pore size between 0.05 and 0.15 μm. The separation membrane is formed by placing a polymer membrane impregnated with an aqueous solution of amino-rich monomers at the bottom of a reactor, and then placing an oil-phase solution of acyl chloride monomers at the top of the polymer membrane, allowing the amino-rich monomers and acyl chloride monomers to react and form a membrane at the water-oil interface. The amino-rich monomers have an aromatic framework structure and abundant amino groups; they possess good and stable water solubility; they can be prepared in a short time and have a high degree of crosslinking. The separation membrane of this invention can achieve rapid and efficient separation of different antibiotic molecules from 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 method for preparing a novel separation membrane with a loose selective layer. 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, desalination, 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 desalination 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 desalination 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 desalination. Thin-film composite membranes, made of polyamide selective layers on porous polymer substrates through interfacial polymerization, dominate the antibiotic desalination membrane market due to their designability and continuous, simple application methods. Currently, the most commonly used aqueous monomers in interfacial polymerization technology are mainly small-molecule monomers (including piperazine, m-phenylenediamine, p-phenylenediamine, etc.). A common characteristic of these monomers during interfacial polymerization is that their diffusion rate is much greater than the formation rate of the selective film, resulting in a dense and thick selective layer. This dense selective layer lacks internal pathways for water molecule and salt ion transport, leading to low pure water flux and high rejection rates for antibiotics and inorganic salts (i.e., limited salt / antibiotic separation efficiency).

[0003] Increasing the free volume within the selective layer has proven to be an effective strategy for preparing highly efficient antibiotic desalination membranes. An effective method to achieve this is to utilize macro-skeletal monomers with rigid and tortuous structures to synthesize antibiotic desalination membranes with loose selective layers. Macro-skeletal monomers are mainly divided into glycoside macromolecules and polyaromatic amines, which diffuse to the interface during interfacial polymerization, forming irregular stacks that result in abundant free volume within the selective layer, providing rapid transport pathways for salt ions and water molecules. Among these, glycoside macromolecules contain abundant reactive groups (-OH). Due to the low reactivity of -OH during interfacial polymerization, the degree of cross-linking in the selective layer is low, leading to large voids within the formed membrane network structure and poor sieving performance in antibiotic and salt applications. On the other hand, amino-rich monomers are considered ideal monomers for preparing antibiotic desalination membranes with loose selective layers due to their high reactivity and uniformly distributed reaction sites. However, the poor water solubility of most amino-rich monomers limits the preparation of antibiotic desalination membranes with loose selective layers via interfacial polymerization. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a separation membrane with a loose selective layer and to achieve rapid and efficient antibiotic desalting performance of the separation membrane.

[0005] The first objective of this application is to provide a method for preparing a desalination separation membrane, characterized in that the method includes the following steps:

[0006] S1. Immerse the polymer membrane in an aqueous solution rich in amino monomers, remove it, remove the surface liquid with a roller, and spread it evenly at the bottom of the reactor.

[0007] S2. Pour the oil phase solution of acyl chloride monomer onto the surface of the polymer membrane treated in S1. The amino-rich monomer and acyl chloride monomer react at the water-oil interface to obtain the desalination separation membrane.

[0008] The amino-rich monomers include one or more of the following: 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), 9,9'-spirobis[fluorene]-2,2', 3,3', 6,6', 7,7'-octaamine.

[0009] The amino-rich monomer possesses a three-dimensional distorted spatial structure due to single-bond rotation or the influence of strong steric hindrance substituents. Furthermore, the amino-rich monomer also exhibits abundant amino reaction sites and good water solubility. Optionally, in one embodiment, the polyacrylamide chloride includes one or more of the following: trimesoyl chloride, terephthaloyl chloride, isophthaloyl chloride, phthaloyl chloride, oxaloyl chloride, malonyl chloride, succinoyl chloride, glutaryl chloride, and adipoyl chloride.

[0010] In one embodiment, the polymer membrane is an ultrafiltration membrane with a pore size of 0.05 to 0.15 μm.

[0011] In one embodiment, the polymer film includes polyethersulfone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose diacetate, cellulose triacetate, cyanoethyl acetate, polysulfone, polysulfonamide, polyarylsulfone, polyvinylidene fluoride, and cellulose.

[0012] In one embodiment, the oil phase solvent includes one or more nonpolar reagents such as alkanes, ether solvents, aromatic hydrocarbons, and ester solvents.

[0013] In one embodiment, the concentration of the amino-rich monomer aqueous solution is 0.02 wt% to 0.08 wt%; and the concentration of the 1,3,5-benzenetricarboxylic acid chloride hexane solution is 0.05 to 0.15 wt%.

[0014] In one implementation, the steps are as follows:

[0015] S1-1. Immerse the polymer membrane in an aqueous solution rich in amino monomers for 5 to 15 minutes. After removing it, use a pressure roller to remove excess aqueous solution from the surface of the polymer membrane and spread it flat at the bottom of the reactor.

[0016] S1-2: Pour the oil phase solution of the acyl chloride monomer onto the surface of the polymer membrane treated in S1, and react at room temperature for 30-60 seconds to obtain the separation membrane.

[0017] In one embodiment, the interfacial polymerization reaction time between the amino-rich monomer and the acyl chloride monomer is 30s to 60s.

[0018] In one embodiment, the 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) is prepared by:

[0019] S2-1. Dissolve 4,4',4”,4”'-methanetetraphenylamine in acetic acid and cool to 0°C. Add acetic anhydride and stir at room temperature for 60 h to obtain a grayish-white suspension. Filter the resulting suspension to remove the precipitate, dissolve it in DMF, pour the solution into ice water, filter out the solid and wash to obtain tetra(4-N-acetaminophenyl)methane.

[0020] S2-2. Cool a mixture of concentrated nitric acid and concentrated sulfuric acid to -10°C, then add tetrakis(4-N-acetaminophenyl)methane. Stir the solution at -10°C for 10 min, then at ambient temperature for 30 min to obtain an orange-red transparent solution. Place the orange-red transparent solution in ice water, filter out the precipitate and wash to obtain N,N',N”,N”'-[methanetetrayltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide;

[0021] S2-3, N,N',N”,N”'-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide was dispersed in a mixed solution of ethanol and sodium hydroxide aqueous solution. The mixed solution was heated under reflux for 2 hours with stirring, then cooled to room temperature and filtered to obtain 4,4',4”,4”'-methanetetramethyltetra(2-nitrobenzyl)amine.

[0022] S2-4. 4,4',4”,4”'-methanetetrayltetra(2-nitroaniline) and tin(II) chloride dihydrate were dispersed in a mixed solution of ethanol and concentrated hydrochloric acid. The mixture was heated under reflux for 24 hours with stirring. After cooling to room temperature, the precipitate was collected by filtration, washed with concentrated hydrochloric acid, dried under reduced pressure, washed again with ethyl acetate, and finally recrystallized in dilute hydrochloric acid solution. Specifically, concentrated HCl solution was slowly added to boiling water containing 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine) until the solution remained transparent. After cooling to room temperature, a crystalline precipitate was formed. The precipitate was collected by filtration and dried to obtain pure 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine).

[0023] In one embodiment, the amino-rich monomer 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) is synthesized via the following steps:

[0024] S2-1-1. Dissolve 1.00 g (2.62 mmol) of 4,4',4”,4”'-methanetetraphenylamine in 40 mL of acetic acid and cool to 0 °C. Slowly add acetic anhydride (50 mL) and stir the resulting mixture at ambient temperature for 60 h. Filter the resulting precipitate, dissolve it in DMF (50 mL), pour the solution onto ice water, filter out the solid and wash with water to obtain tetra(4-N-acetamidophenyl)methane, which is a white powder.

[0025] S2-1-2. Cool a mixture of 5 mL concentrated nitric acid (65%) and 5 mL concentrated sulfuric acid (99%) to -10 °C, then add tetrakis(4-N-acetaminophenyl)methane (330 mg, 0.46 mmol). Stir the solution at -10 °C for 10 min, then stir at ambient temperature for 30 min to obtain an orange-red transparent solution. Place the orange-red transparent solution in 50 mL of ice water, quickly filter out the yellow precipitate, and wash with water (50 mL) to obtain N,N',N”,N”'-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide, which is a yellow powder.

[0026] S2-1-3. N,N',N”,N”'-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide (2.24 g, 3.07 mmol) was dispersed in a solution of water (14 mL) with ethanol (300 mL) and sodium hydroxide (0.81 g, 20.13 mmol) added slowly. The mixture was heated under reflux for 2 h with stirring, and then cooled to room temperature. The solution was concentrated by evaporating ethanol on a rotary evaporator. Then water (100 mL) was added to the separated product and collected in a Buchner funnel to give 4,4',4”,4”'-methanetetramethyltetra(2-nitrobenzyl) as a yellow powder.

[0027] S2-1-4. 4,4',4”,4”'-methanetetrayltetra(2-nitroaniline) (1.50 g, 2.68 mmol) and tin(II) chloride dihydrate (24 g) were dispersed in a mixed solution of ethanol (150 mL) and concentrated hydrochloric acid (90 mL), and refluxed with stirring for 24 h. After cooling the reaction mixture to room temperature, the milky white precipitate was collected by filtration, washed with concentrated hydrochloric acid (3 × 24 mL), and dried under reduced pressure (0.05 mmHg). The product was then washed with ethyl acetate to remove unbound HCl. The product was recrystallized from dilute hydrochloric acid solution by slowly adding concentrated HCl solution to boiling water containing 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine) until the solution remained transparent. After cooling to room temperature, a milky white crystalline precipitate was formed. The precipitate was collected by filtration and dried to obtain pure 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine) as a white powder.

[0028] In one embodiment, the preparation method of the 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine is as follows:

[0029] S3-1. Dissolve 2,2',7,7'-tetraammonium-9,9'-spirobisfluorene tetrachloride in acetic acid and cool to 0°C. Add acetic anhydride and stir at ambient temperature to obtain a grayish-white suspension. After precipitating and filtering the suspension, dissolve it in DMF and pour the solution onto ice water. Filter out the solid and wash with water to obtain 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene.

[0030] S3-2. Cool a mixture of concentrated nitric acid and concentrated sulfuric acid to -10°C, then add 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene. Stir the solution at -10°C for 10 minutes, then stir at ambient temperature for 30 minutes. Place the solution in ice water, filter the precipitate and wash with water to obtain 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene.

[0031] S3-3. 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene was dispersed in an aqueous solution of ethanol and sodium hydroxide. The mixture was refluxed under stirring, then cooled to room temperature, concentrated by evaporation, and water was added. The mixture was then filtered to obtain 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobisfluorene hydrogen chloride.

[0032] S3-4. 2,2',7,7'-Tetraamino-3,3',6,6'-Tetranitro-9,9'-spirobisfluorene hydrogen chloride and tin(II) chloride dihydrate were added to a mixed solution of ethanol and concentrated hydrochloric acid. The mixture was heated to reflux with stirring, cooled to room temperature, and the precipitate was collected by filtration. The precipitate was washed with concentrated hydrochloric acid, dried under reduced pressure, washed with ethyl acetate, and recrystallized in dilute hydrochloric acid solution. Specifically, concentrated HCl solution was slowly added to boiling water containing 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine until the solution remained transparent. After cooling to room temperature, a crystalline precipitate was formed. The precipitate was collected by filtration and dried to obtain pure 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine.

[0033] In one embodiment, the amino-rich monomer 9,9'-spirobi[fluorene]-2,2',3,3',6,6',7,7'-octaamine is synthesized using the following steps:

[0034] S3-1-1. Dissolve 1.00 g (2.65 mmol) of 2,2',7,7'-tetraammonium-9,9'-spirobisfluorene hydrogen chloride in acetic acid (40 mL) and cool to 0 °C. Slowly add acetic anhydride (50 mL) and stir the resulting mixture at ambient temperature for 60 h to obtain a grayish-white suspension. Filter the grayish-white suspension to precipitate, dissolve it in DMF (50 mL), pour the solution into ice water, filter out the solid, and wash with water to obtain 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene, which is a white solid.

[0035] S3-1-2. Cool a mixture of 5 mL concentrated nitric acid and 5 mL concentrated sulfuric acid to -10 °C, then add 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene (330 mg, 0.46 mmol). Stir the solution at -10 °C for 10 minutes, then at ambient temperature for 30 minutes. Pour the solution into an orange-red solution and place it in 50 mL of ice water. Filter out the yellow precipitate and wash it with water (50 mL) to obtain 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene, which is a yellow powder.

[0036] S3-1-3. Compound 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene (2.24 g, 3.09 mmol) was dispersed in a solution of water (14 mL) with ethanol (300 mL) and sodium hydroxide (0.81 g, 20.13 mmol) added slowly. The mixture was refluxed with stirring for 2 h, then cooled to room temperature. The solution was concentrated by evaporating ethanol on a rotary evaporator, and then water (100 mL) was added to the separated product and collected in a Buchner funnel to give 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobisfluorene hydrogen chloride as a yellow powder.

[0037] S3-1-4. The suspension of 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobromene tetrachloride (1.50 g, 2.70 mmol) and tin(II) chloride dihydrate (24 g) in 150 mL of ethanol and 90 mL of concentrated hydrochloric acid was added to a three-necked round-bottom flask (500 mL). The mixture was refluxed with stirring for 24 hours. After cooling the reaction mixture to room temperature, the milky white precipitate was collected by filtration, washed with concentrated hydrochloric acid (3 × 24 mL), and dried under reduced pressure. The product was dried (0.05 mmHg), and then washed with ethyl acetate to remove unbound HCl. The product was recrystallized from dilute hydrochloric acid solution. Concentrated HCl solution was slowly added to boiling water containing 9,9'-spirodi[fluorene]-2,2',3,3',6,6',7,7'-octaamine until the solution remained transparent. After cooling to room temperature, milky white crystals were formed. After filtration, collection and drying, 9,9'-spirodi[fluorene]-2,2',3,3',6,6',7,7'-octaamine was obtained as a white powder.

[0038] The second objective of this application is to provide a desalination separation membrane prepared by the above method, wherein the membrane has a thickness of 20-100 nm and a pore size of 0.9-3.6 nm.

[0039] The separation membrane can be rapidly prepared and has a loose selective layer structure; it enables efficient and precise sieving of antibiotic molecules and salts. The membrane has a suitable pore size (salt ions and water molecules can pass through quickly, while antibiotic molecules cannot), achieving efficient and precise separation of antibiotics and salts through a pore size sieving mechanism. Furthermore, the membrane surface is negatively charged, resulting in better retention of electronegative antibiotics under the Donnan effect mechanism.

[0040] The third objective of this application is to provide an application of the separation membrane prepared by the above method, characterized in that the separation membrane is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 2 to 6 bar.

[0041] The separation membrane is installed on the cross-flow separation device and pre-pressed with water pressure of 4-8 bar for 30 minutes, which allows the separation membrane to maintain good structural integrity.

[0042] In one embodiment, the separation membrane is installed on a cross-flow separation device for separation experiments of antibiotic / salt mixed solution systems. The operating temperature is room temperature, and the operating pressure is 2–6 bar. The retention rate for antibiotics with a molecular weight greater than 550 Da or electronegative antibiotics with a molecular weight greater than 440 Da reaches over 99%, while the retention rate for salts is less than 25%.

[0043] Beneficial effects:

[0044] This invention provides a method for preparing a loosely selective layer separation membrane. Based on the rigid, three-dimensionally twisted structure of the amino-rich monomer, its abundant amino reaction sites, and good water solubility, irregularly stacked pores are formed at the water-oil interface during interfacial polymerization. Through the rapid cross-linking reaction between the abundant amino groups and acyl chloride monomers, a loosely selective layer separation membrane is formed (salt ions and water molecules can pass through rapidly, while antibiotic molecules cannot).

[0045] The separation membrane provided by this invention, due to the abundance of amino groups in its amino-rich monomers, exhibits positive charge due to the ionization of unreacted amino groups in aqueous solution, thereby increasing the surface potential of the separation membrane. Therefore, the surface charge of the membrane can be controlled by adjusting the concentration of the amino-rich monomer aqueous solution, enabling precise sieving of antibiotic molecules with different charges based on the Donnan effect.

[0046] The separation membrane provided by this invention has a suitable pore size (salt ions and water molecules can pass through quickly, while antibiotic molecules cannot pass through), and can achieve efficient and precise separation of antibiotics and salts under the pore size sieving mechanism; the separation membrane surface is negatively charged, and based on the Donnan effect, it has a better retention effect on electronegative antibiotics under the same molecular size. Attached Figure Description

[0047] Figure 1 The molecular structures of monomers commonly used in the preparation of antibiotic desalination membranes in IP ((a) piperazine, (b) m-phenylenediamine) and amino-rich monomers (4,4',4',4''-methanetetramethyltetra(1,2-phenylenediamine)(c), 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine(d))

[0048] Figure 2 Synthetic routes for 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine) (a) and 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine (b) Detailed Implementation

[0049] The synthetic route for the amino-rich monomer 4,4',4',4''-methanetetramethyltetra(1,2-phenylenediamine) is shown below. Figure 2 The synthesis steps are as follows:

[0050] S1. Dissolve 1.00 g (2.62 mmol) of 4,4',4”,4”'-methanetetraphenylamine in acetic acid (40 mL) and cool to 0 °C. Slowly add acetic anhydride (50 mL). Stir the resulting mixture at ambient temperature for 60 h to obtain a grayish-white suspension. Filter the precipitate from the suspension, dissolve it in DMF (50 mL), and pour the solution into ice water. Filter out the solid, wash with water, and dry to obtain tetra(4-N-acetaminophenyl)methane as a white powder.

[0051] S2. Cool a mixture of 5 mL concentrated nitric acid (65%) and 5 mL concentrated sulfuric acid (99%) to -10 °C, then add tetrakis(4-N-acetaminophenyl)methane (330 mg, 0.46 mmol). Stir the solution at -10 °C for 10 min, then at ambient temperature for 30 min to obtain an orange-red transparent solution. Pour the orange-red transparent solution into 50 mL of ice water, filter out the yellow precipitate, wash with water (50 mL), and dry to obtain N,N',N”,N”'-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide, which is a yellow powder;

[0052] S3. In a three-necked round-bottom flask (500 mL), compound 4 (2.24 g, 3.07 mmol) was dispersed in a solution of water (14 mL) with ethanol (300 mL) and sodium hydroxide (0.81 g, 20.13 mmol) added slowly. The mixture was refluxed with stirring for 2 h and then cooled to room temperature. The solution was concentrated by evaporating ethanol on a rotary evaporator. Water (100 mL) was then added to the separated product, which was collected in a Buchner funnel and dried to give 4,4',4”,4”'-methanetetramethyltetra(2-nitroaniline) as a yellow powder.

[0053] S4. A suspension of 4,4',4”,4”'-methanetetrayltetra(2-nitroaniline) and tin(II) dihydrate (24 g) was added to a three-necked round-bottom flask (500 mL) in ethanol (150 mL × 120 mmol) and concentrated hydrochloric acid (90 mL) and refluxed with stirring for 24 hours. After cooling the reaction mixture to room temperature, the milky white precipitate was collected by filtration, washed with concentrated hydrochloric acid (3 × 24 mL), and dried under reduced pressure (0.05 mmHg). The product was then further washed with ethyl acetate to remove unbound HCl. The product was recrystallized from dilute hydrochloric acid solution. Concentrated HCl solution was slowly added to boiling water containing 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine) until the solution remained clear. After cooling to room temperature, milky white crystals formed, which were collected by filtration and dried to give 4,4',4”,4”'-methanetetrayltetra(phenyl-1,2-diamine).

[0054] The synthetic route for the amino-rich monomer 9,9'-spirobi[fluorene]-2,2',3,3',6,6',7,7'-octaamine is shown in [reference needed]. Figure 2 The synthesis steps are as follows:

[0055] S1. Dissolve 1.00 g (2.65 mmol) of 2,2',7,7'-tetraammonium-9,9'-spirobisfluorene tetrachloride in acetic acid (40 mL) and cool to 0 °C. Slowly add acetic anhydride (50 mL). Stir the resulting mixture at ambient temperature for 60 hours to obtain a grayish-white suspension. Filter the precipitate from the suspension, dissolve it in DMF (50 mL), and pour the solution into ice water. Filter off the solid, wash with water, and dry to obtain 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene, a colorless solid.

[0056] S2. Cool a mixture of 5 mL concentrated nitric acid and 5 mL concentrated sulfuric acid to -10 °C, then add 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene (330 mg, 0.46 mmol). Stir the solution at -10 °C for 10 minutes, then at ambient temperature for 30 minutes. Pour the orange-red solution into 50 mL of ice water, filter out the yellow precipitate, wash with water (50 mL), and dry to obtain 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene, a yellow solid.

[0057] S3. In a three-necked round-bottom flask (500 mL), 2.24 g (3.09 mmol) of compound 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene (2.24 g, 3.09 mmol) was dispersed in a solution of 14 mL of water with ethanol (300 mL) and sodium hydroxide (0.81 g, 20.13 mmol) added slowly. The mixture was refluxed with stirring for 2 h and then cooled to room temperature. The solution was concentrated by evaporating ethanol on a rotary evaporator. Water (100 mL) was then added to the separated product, which was collected in a Buchner funnel and dried to give 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobisfluorene hydrogen chloride as a yellow powder.

[0058] S4. A suspension of 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobisfluorene hydrogen chloride (1.5 g, 2.7 mmol) and tin(II) chloride dihydrate (24 g) in 150 mL of ethanol and 90 mL of concentrated hydrochloric acid was added to a three-necked round-bottom flask (500 mL) and refluxed with stirring for 24 hours. After cooling the reaction mixture to room temperature, the milky white precipitate was collected by filtration, washed with concentrated hydrochloric acid (3 × 24 mL), and dried under reduced pressure (0.05 mmHg). The product was then further washed with ethyl acetate to remove unbound HCl. The product was recrystallized from dilute hydrochloric acid solution. Concentrated HCl solution was slowly added to boiling water containing 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine until the solution remained clear. After cooling to room temperature, milky white crystals are formed. After filtration, collection and drying, pure 9,9'-spirodi[fluorene]-2,2',3,3',6,6',7,7'-octaamine is obtained as a white powder.

[0059] Table 1. Molecular weight, molecular size, and charge information of antibiotics and salt ions.

[0060]

[0061] Example 1: Preparation of Separation Membrane-1

[0062] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0063] The method for preparing the above-mentioned separation membrane-1 includes the following steps:

[0064] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0065] S2. A solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane was poured onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then allowed to stand at room temperature for 40 s to obtain separation membrane-1.

[0066] Example 2: Separation Membrane-1 Antibiotic Desalination Performance Test

[0067] Separation membrane-1 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0068] The retention rates of single-component antibiotics and salts by the separation membrane-1 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in a single system, the separation membrane-1 exhibited retention rates of 99.8%, 99.5%, 78.9%, 67.5%, 69.5% for doxorubicin, 22.0%, 20.6%, 11.9%, and 11.2% for cefazolin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0069] The retention rates of antibiotics and salts in the mixed components by the separation membrane-1 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-1 in the mixed system were 99.4% / 11.9%, 99.8% / 12.0%, 78.5% / 11.9%, 67.5% / 11.9%, and 71.2% / 11.9%, respectively, following the pore size sieving principle and the Donnan effect.

[0070] Example 3: Preparation of Separation Membrane-2

[0071] In this embodiment, the amino-rich monomer used is 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine, and the polymer film is polyethersulfone.

[0072] The method for preparing the above-mentioned separation membrane-2 includes the following steps:

[0073] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% 9,9'-spirodi[fluorene]-2,2',3,3',6,6',7,7'-octaamine for 10 minutes. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0074] S2. A solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane was poured onto the surface of a polyethersulfone polymer rich in an aqueous solution of 9,9'-spirodi[fluorene]-2,2',3,3',6,6',7,7'-octaamine, and then allowed to stand at room temperature for 30 seconds to obtain separation membrane-2.

[0075] Example 4: Antibiotic Desalination Performance Test of Separation Membrane-2

[0076] Separation membrane-2 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0077] The retention rates of single-component antibiotics and salts by the separation membrane-2 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single-component systems, the separation membrane-2 exhibited retention rates of 99.8%, 99.7%, 77.8%, 70.5%, 65.4%, 68.5% for doxorubicin, 21.5%, 19.7%, 11.4%, and 10.7% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0078] The retention rates of antibiotics and salts in the mixed components by the separation membrane-2 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-2 were 99.4% / 11.4%, 99.8% / 11.3%, 78.5% / 11.3%, 67.5% / 11.6%, and 71.2% / 11.5%, respectively, following the pore size sieving principle and the Donnan effect.

[0079] Example 5: Preparation of Separation Membrane-3

[0080] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0081] The method for preparing the above-mentioned separation membrane-3 includes the following steps:

[0082] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.04 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 minutes. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0083] S2. A solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane was poured onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then allowed to stand at room temperature for 40 s to obtain the separation membrane-3.

[0084] Example 6: Separation Membrane - Antibiotic Desalination Performance Test

[0085] Separation membrane-3 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0086] The retention rates of single-component antibiotics and salts by the separation membrane-3 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single-component systems, the separation membrane-3 exhibited retention rates of 97.4%, 98.0%, 75.6%, 61.5%, 64.6% for doxorubicin, 21.8%, 20.1%, 11.8%, and 10.9% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0087] The retention rates of antibiotics and salts in the mixed components by the separation membrane-3 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-3 in the mixed system were 97.6% / 11.9%, 97.5% / 11.9%, 76.8% / 11.8%, 62.5% / 11.8%, and 65.5% / 11.8%, respectively, following the pore size sieving principle and the Donnan effect.

[0088] Example 7 Preparation of Separation Membrane-4

[0089] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0090] The method for preparing the above-mentioned separation membrane-4 includes the following steps:

[0091] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.06 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 minutes. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0092] S2. A solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane was poured onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then allowed to stand at room temperature for 40 s to obtain the separation membrane-4.

[0093] Example 8: Separation Membrane - Antibiotic Desalination Performance Test

[0094] Separation membrane-4 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0095] The retention rates of single-component antibiotics and salts by the separation membrane-4 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single-component systems, the separation membrane-4 exhibited retention rates of 95.4%, 96.3%, 71.2%, 60.5%, 62.6% for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and 21.7%, 19.9%, 11.6%, 10.8% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0096] The retention rates of antibiotics and salts in the mixed components by the separation membrane-4 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-4 in the mixed system were 95.3% / 11.7%, 95.6% / 11.7%, 71.5% / 11.7%, 60.8% / 11.6%, and 63.5% / 11.7%, respectively, following the pore size sieving principle and the Donnan effect.

[0097] Example 9: Preparation of Separation Membrane-5

[0098] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0099] The method for preparing the above-mentioned separation membrane-5 includes the following steps:

[0100] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.08 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom container.

[0101] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-5.

[0102] Example 10: Separation Membrane - Antibiotic Desalination Performance Test

[0103] The separation membrane-5 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0104] The retention rates of single-component antibiotics and salts by the separation membrane-5 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single systems, the separation membrane-5 exhibited retention rates of 94.8%, 94.9%, 70.3%, 58.5%, 61.5% for doxorubicin, 21.4%, 19.5%, 11.5%, and 10.8% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0105] The retention rates of antibiotics and salts in mixed components by the separation membrane-5 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-5 were 95.0% / 11.5%, 95.1% / 11.5%, 68.5% / 11.6%, 58.3% / 11.6%, and 62.5% / 11.7%, respectively, following the pore size sieving principle and the Donnan effect.

[0106] Example 11 Preparation of Separation Membrane-6

[0107] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0108] The method for preparing the above-mentioned separation membrane-6 includes the following steps:

[0109] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0110] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 30 seconds to obtain the separation membrane-6.

[0111] Example 12 Separation Membrane - Antibiotic Desalination Performance Test

[0112] The separation membrane-6 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0113] The retention rates of single-component antibiotics and salts by the Separation Membrane-6 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. Results showed that in single-component systems, the Separation Membrane-6 exhibited retention rates of 93.5%, 94.1%, 70.2%, 57.6%, 62.3% for doxorubicin, 18.1%, 16.5%, 10.4%, and 9.8% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0114] The retention rates of antibiotics and salts in mixed components by the separation membrane-6 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-6 in the mixed system were 94.2% / 10.5%, 99.8% / 10.5%, 78.5% / 10.5%, 67.5% / 10.4%, and 71.2% / 10.5%, respectively, following the pore size sieving principle and the Donnan effect.

[0115] Example 13 Preparation of Separation Membrane-7

[0116] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0117] The method for preparing the above-mentioned separation membrane-7 includes the following steps:

[0118] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0119] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 50 s to obtain the separation membrane-7.

[0120] Example 14: Desalination Performance Test of Separation Membrane-7 for Antibiotics

[0121] The separation membrane-7 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0122] The retention rates of single-component antibiotics and salts by the separation membrane-7 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in a single system, the separation membrane-7 exhibited retention rates of 99.9% for doxorubicin, 99.9% for cefazolin, 81.2% for tetracycline, 69.2% for chloramphenicol, 73.5% for norfloxacin, and 22.2% for sodium sulfate, 21.3% for magnesium sulfate, 12.1% for sodium chloride, and 11.4% for potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0123] The retention rates of antibiotics and salts in mixed components by the separation membrane-7 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-7 were 99.9% / 12.1%, 99.9% / 12.2%, 82.3% / 12.2%, 70.5% / 12.1%, and 74.6% / 12.2%, respectively, following the pore size sieving principle and the Donnan effect.

[0124] Example 15 Preparation of Separation Membrane-8

[0125] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0126] The method for preparing the above-mentioned separation membrane-8 includes the following steps:

[0127] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0128] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 60 s to obtain the separation membrane-8.

[0129] Example 16: Separation Membrane-8 Antibiotic Desalination Performance Test

[0130] The separation membrane-8 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0131] The retention rates of single-component antibiotics and salts by the Separation Membrane-8 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. Results showed that in single-component systems, the Separation Membrane-8 exhibited retention rates of 99.9%, 99.9%, 84.2%, 72.3%, 76.5% for doxorubicin, 23.0%, 22.5%, 12.5%, and 11.9% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0132] The retention rates of antibiotics and salts in the mixed components by the separation membrane-8 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride in the mixed system were 99.9% / 12.7%, 99.9% / 12.7%, 85.0% / 12.7%, 74.2% / 12.8%, and 78.5% / 12.7%, respectively, following the pore size sieving principle and the Donnan effect.

[0133] Example 17 Preparation of Separation Membrane-9

[0134] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyacrylonitrile.

[0135] The method for preparing the above-mentioned separation membrane-9 includes the following steps:

[0136] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0137] S2. A solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride in n-hexane was poured onto the surface of a polyacrylonitrile polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then allowed to stand at room temperature for 40 seconds to obtain the separation membrane-9.

[0138] Example 18: Separation Membrane-9 Antibiotic Desalination Performance Test

[0139] The separation membrane-9 is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0140] The retention rates of single-component antibiotics and salts by the Separation Membrane-9 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. Results showed that in single-component systems, the Separation Membrane-9 exhibited retention rates of 99.7%, 99.8%, 77.1%, 66.1%, 68.7% for doxorubicin, 21.5%, 20.1%, 11.5%, and 10.8% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0141] The retention rates of antibiotics and salts in mixed components by the separation membrane-9 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in the mixed systems, the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-9 were 99.7% / 11.5%, 99.8% / 11.6%, 77.5% / 11.6%, 67.2% / 11.5%, and 70.2% / 11.6%, respectively, following the pore size sieving principle and the Donnan effect.

[0142] Example 19 Preparation of Separation Membrane-10

[0143] The method for preparing the above-mentioned separation membrane-10 includes the following steps:

[0144] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 5 minutes. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0145] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-10.

[0146] Example 20 Separation Membrane-10 Antibiotic Desalination Performance Test

[0147] The separation membrane-10 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0148] The retention rates of single-component antibiotics and salts by the Separation Membrane-10 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. Results showed that in single-component systems, the Separation Membrane-10 exhibited retention rates of 89.2%, 87.5%, 72.2%, 52.5%, 54.6% for doxorubicin, 17.6%, 15.8%, 7.5%, and 6.6% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0149] The retention rates of antibiotics and salts in mixed components by the separation membrane-10 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-10 in the mixed system were 89.4% / 7.8%, 88.6% / 7.8%, 73.5% / 7.7%, 53.0% / 7.8%, and 55.2% / 7.8%, respectively, following the pore size sieving principle and the Donnan effect.

[0150] Example 21 Preparation of Separation Membrane-11

[0151] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0152] The method for preparing the above-mentioned separation membrane-11 includes the following steps:

[0153] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 15 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom container.

[0154] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-11.

[0155] Example 22 Separation Membrane-11 Antibiotic Desalination Performance Test

[0156] Separation membrane-11 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0157] The retention rates of single-component antibiotics and salts by the separation membrane-11 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single systems, the separation membrane-11 exhibited retention rates of 99.8%, 99.6%, 78.8%, 67.5%, 68.6% for doxorubicin, 22.1%, 20.8%, 11.8%, and 11.1% for cefazolin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0158] The retention rates of antibiotics and salts in mixed components by the separation membrane-11 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-11 in the mixed system were 99.8% / 11.8%, 99.7% / 11.8%, 79.0% / 11.8%, 68.2% / 11.8%, and 71.7% / 11.8%, respectively, following the pore size sieving principle and the Donnan effect.

[0159] Example 23 Preparation of Separation Membrane-12

[0160] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0161] The method for preparing the above-mentioned separation membrane-12 includes the following steps:

[0162] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0163] S2. Pour a solution of 0.1 wt% terephthaloyl chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-12.

[0164] Example 24: Test of Antibiotic Desalination Performance of Separation Membrane-12

[0165] Separation membrane-12 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0166] The retention rates of single-component antibiotics and salts by the separation membrane-12 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single-component systems, the separation membrane-12 exhibited retention rates of 99.9%, 99.8%, 80.2%, 69.5%, 74.5% for doxorubicin, 22.6%, 21.1%, 12.3%, and 11.5% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0167] The retention rates of antibiotics and salts in mixed components by the separation membrane-12 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-12 in the mixed system were 99.9% / 12.3%, 99.9% / 12.2%, 81.2% / 12.3%, 70.0% / 12.3%, and 75.6% / 12.4%, respectively, following the pore size sieving principle and the Donnan effect.

[0168] Example 25 Preparation of Separation Membrane-13

[0169] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0170] The method for preparing the above-mentioned separation membrane-13 includes the following steps:

[0171] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0172] S2. Pour a solution of 0.1 wt% ethyl 1,3,5-benzenetricarboxylate chloride onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-13.

[0173] Example 26 Separation Membrane-13 Antibiotic Desalination Performance Test

[0174] Separation membrane-13 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0175] The retention rates of single-component antibiotics and salts by the separation membrane-13 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single systems, the separation membrane-13 exhibited retention rates of 99.7%, 99.7%, 77.8%, 66.7%, 68.9% for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and 21.6%, 20.9%, 12.5%, and 11.4% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0176] The retention rates of antibiotics and salts in mixed components by the separation membrane-13 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-13 in the mixed system were 99.8% / 12.6%, 99.9% / 12.6%, 78.1% / 12.6%, 66.7% / 12.6%, and 69.8% / 12.5%, respectively, following the pore size sieving principle and the Donnan effect.

[0177] Example 27 Preparation of Separation Membrane-14

[0178] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0179] The method for preparing the above-mentioned separation membrane-14 includes the following steps:

[0180] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0181] S2. Pour a solution of 0.05 wt% ethyl 1,3,5-benzenetricarboxylate chloride onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-14.

[0182] Example 28 Separation Membrane-14 Antibiotic Desalination Performance Test

[0183] Separation membrane-14 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0184] The retention rates of single-component antibiotics and salts by the separation membrane-14 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single-component systems, the separation membrane-14 exhibited retention rates of 86.3%, 84.6%, 73.9%, 63.5%, 66.4% for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0185] The retention rates of antibiotics and salts in mixed components by the separation membrane-14 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-14 in the mixed system were 84.6% / 13.6%, 83.9% / 13.7%, 74.6% / 13.7%, 64.0% / 13.8%, and 67.1% / 13.8%, respectively, following the pore size sieving principle and the Donnan effect.

[0186] Example 29 Preparation of Separation Membrane-15

[0187] In this embodiment, the amino-rich monomer used is 4,4',4",4"'-methanetetramethyltetra(1,2-phenylenediamine), and the polymer film is polyethersulfone.

[0188] The method for preparing the above-mentioned separation membrane-15 includes the following steps:

[0189] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine) for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom-made container.

[0190] S2. Pour a solution of 0.15 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4'',4''-methanetetramethyltetra(1,2-phenylenediamine), and then let it stand at room temperature for 40 s to obtain the separation membrane-15.

[0191] Example 30 Separation Membrane-15 Antibiotic Desalination Performance Test

[0192] The separation membrane-15 is installed on a cross-flow separation device to separate antibiotics and salts at room temperature and an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0193] The retention rates of single-component antibiotics and salts by the separation membrane-15 were investigated. Antibiotic retention was monitored using a UV spectrophotometer, while salt retention was monitored using a conductivity meter. The results showed that in single systems, the separation membrane-15 exhibited retention rates of 99.9%, 99.4%, 79.2%, 68.0%, 71.3% for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and 23.6%, 21.2%, 12.4%, 11.8% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, following the principles of pore size sieving and the Donnan effect.

[0194] The retention rates of antibiotics and salts in mixed components by the separation membrane-15 were investigated. 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 doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-15 in the mixed system were 99.9% / 11.9%, 99.6% / 11.8%, 80.1% / 11.9%, 69.3% / 11.9%, and 72.6% / 11.9%, respectively, following the pore size sieving principle and the Donnan effect.

[0195] Comparative Example 1: Effect of using small molecule ammonia monomers to prepare separation membranes on their antibiotic desalting performance

[0196] In this embodiment, the aqueous monomer used is piperazine, and the polymer membrane is polyethersulfone.

[0197] The method for preparing the above-mentioned separation membrane includes the following steps:

[0198] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.01 wt% piperazine for 10 minutes. After removing it, use a pressure roller to remove excess aqueous solution from the surface and then place it in a custom container.

[0199] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in piperazine aqueous solution, and then let it stand at room temperature for 40 s to obtain a separation membrane.

[0200] The separation membrane is installed on a cross-flow separation device to separate antibiotics and salts at room temperature, with an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0201] The retention rates of the separation membrane for single-component antibiotics and salts were investigated. 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 separation membrane-1 exhibited retention rates of 99.9%, 99.8%, 90.5%, 82.6%, 87.6% for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and 90.5%, 89.5%, 70.6%, 67.5% for sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively, adhering to the principle of pore size sieving.

[0202] The retention rates of antibiotics and salts in the mixed components by the separation membrane were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the separation membrane-1 exhibited retention rates of 99.9% / 67.6%, 99.9% / 67.8%, 90.5% / 67.8%, 83.2% / 67.8%, and 88.0% / 67.7% for doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride, respectively, following the principle of pore size sieving.

[0203] Compared with Comparative Example 1, it was found that the separation membrane prepared by interfacial polymerization of small-molecule amino monomers with 1,3,5-benzenetriacyl chloride, although it had a high antibiotic retention effect, also showed a significant increase in the retention rate of salt ions, ultimately resulting in poor antibiotic / salt selectivity.

[0204] Comparative Example 2: Effect of using aromatic amines to prepare separation membranes on their antibiotic desalting performance

[0205] In this embodiment, the aqueous monomer used is 4,4',4”,4”'-methanetetraphenylamine, and the polymer membrane is polyethersulfone.

[0206] The method for preparing the above-mentioned separation membrane includes the following steps:

[0207] S1. Immerse the polyethersulfone polymer film in an aqueous suspension containing 0.02 wt% 4,4',4”,4”'-methanetetraphenylamine for 10 min. Remove the film and use a pressure roller to remove excess aqueous solution from the surface. Then place the film in a custom container.

[0208] S2. Pour a solution of 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride n-hexane onto the surface of a polyethersulfone polymer rich in an aqueous solution of 4,4',4”,4”'-methanetetraphenylamine, and then let it stand at room temperature for 40 s to obtain a separation membrane.

[0209] The separation membrane is installed on a cross-flow separation device to separate antibiotics and salts at room temperature, with an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0210] The retention rates of the separation membrane for single-component antibiotics and salts were investigated. 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 retention rates of separation membrane-1 for doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride were 45.6%, 43.5%, 42.2%, 39.5%, 39.2% and 4.5%, 4.4%, 3.2%, 2.9%, respectively.

[0211] The retention rates of antibiotics and salts in the mixed components by the separation membrane were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the retention rates of doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride by the separation membrane-1 were 45.7% / 3.1%, 43.6% / 3.1%, 43.0% / 2.9%, 39.8% / 2.9%, and 37.2% / 2.9%, respectively, following the principle of pore size sieving.

[0212] A comparison with Comparative Example 2 revealed that the poor water solubility of aromatic amines prevents amines and acyl chlorides from forming a dense selective layer at the water-n-hexane interface, resulting in poor retention performance of the separation membrane for antibiotics and salt ions.

[0213] Comparative Example 3: Effect of using glycoside monomers to prepare separation membranes on their antibiotic desalting performance

[0214] In this embodiment, the aqueous monomer used is steviol glycoside, and the polymer membrane is polyethersulfone.

[0215] The method for preparing the above-mentioned separation membrane includes the following steps:

[0216] S1. Immerse the polyethersulfone polymer film in an aqueous solution containing 0.02 wt% steviol glycosides for 10 minutes. After removing it, use a pressure roller to remove excess aqueous solution from the surface and then place it in a custom container.

[0217] S2. Pour a solution containing 0.1 wt% 1,3,5-benzenetricarboxylic acid chloride hexane onto the surface of a polyethersulfone polymer rich in steviol glycoside aqueous solution, and then let it stand at room temperature for 40 seconds to obtain a separation membrane.

[0218] The separation membrane is installed on a cross-flow separation device to separate antibiotics and salts at room temperature, with an operating pressure of 3 bar. The selected antibiotic molecules and salts are doxorubicin, cefazolin, tetracycline, chloramphenicol, norfloxacin, sodium sulfate, magnesium sulfate, potassium chloride, and sodium chloride.

[0219] The retention rates of the separation membrane for single-component antibiotics and salts were investigated. 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 separation membrane-1 exhibited retention rates of 80.5%, 75.6%, 74.5%, 62.6%, 64.5% for doxorubicin, 22.6%, 20.8%, 13.6%, and 11.9% for cefazolin, tetracycline, chloramphenicol, norfloxacin, and sodium sulfate, magnesium sulfate, sodium chloride, and potassium chloride, respectively.

[0220] The retention rates of antibiotics and salts in the mixed components by the separation membrane were investigated. Antibiotic retention was monitored using a UV spectrophotometer, and salt retention was monitored using a conductivity meter. The results showed that in the mixed system, the retention rates of membrane-1 for doxorubicin / sodium chloride, cefazolin / sodium chloride, tetracycline / sodium chloride, chloramphenicol / sodium chloride, and norfloxacin / sodium chloride were 81.0% / 13.7%, 77.1% / 13.7%, 75.9% / 13.7%, 63.4% / 13.8%, and 65.6% / 13.7%, respectively, following the principle of pore size sieving.

[0221] Compared with Comparative Example 3, it was found that although steviol glycosides have a three-dimensional twisted spatial structure and abundant reactive groups (-OH), the reactivity between -OH and acyl chloride is lower than that between -NH2 and -OH. Therefore, they cannot quickly form a highly cross-linked selective layer during interfacial polymerization, thus exhibiting poor antibiotic desalting effect.

Claims

1. A method for producing a desalination separation membrane, characterized by, The method includes the following steps: S1. Immerse the polymer membrane in an aqueous solution rich in amino monomers, remove it, remove excess liquid from the surface of the polymer membrane, and spread it evenly at the bottom of the reactor. S2. Pour the oil phase solution of the acyl chloride monomer into the reactor described in S1, so that the amino-rich monomer and the acyl chloride monomer react at the water-oil interface to obtain the desalination separation membrane. The amino-rich monomer is 4,4',4'',4'''-methanetetramethyltetramethyltetramethyl(1,2-phenylenediamine) or 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine; the structural formula of 4,4',4'',4'''-methanetetramethyltetramethyltetramethyl(1,2-phenylenediamine) is as follows: ； The desalination membrane has a loose selective layer structure; the pore size is 0.9~3.6 nm; salt ions and water molecules can pass through quickly, while antibiotic molecules cannot pass through.

2. The method of claim 1, wherein the membrane is a desalination separation membrane. The polymer membrane is an ultrafiltration membrane with a pore size of 0.05~0.15μm.

3. The method of claim 1, wherein the membrane is a desalination separation membrane. Polymer membranes include polyethersulfone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose diacetate, cellulose triacetate, cyanoethyl acetate, polysulfone, polysulfonamide, polyarylsulfone, polyvinylidene fluoride, and cellulose; The acyl chloride monomers include one or more of the following: pyromellitic terephthaloyl chloride, terephthaloyl chloride, isophthaloyl chloride, orthophthaloyl chloride, oxaloyl chloride, malonyl chloride, succinic chloride, glutaryl chloride, and adipyl chloride; The oil phase solution includes one or more of the following: alkanes, ether solvents, aromatic hydrocarbons, and ester solvents.

4. The method of claim 1, wherein the membrane is a desalination separation membrane. The concentration of the amino-rich monomer aqueous solution is 0.02 wt% to 0.08 wt%; the concentration of the acyl chloride monomer oil phase solution is 0.05 to 0.15 wt%.

5. The method of claim 1, wherein the desalination membrane is a separation membrane. The steps are as follows: S1-1. Immerse the polymer membrane in an aqueous solution rich in amino monomers for 5-20 minutes. After removing it, use a pressure roller to remove excess aqueous solution from the surface of the polymer membrane and spread it flat at the bottom of the reactor. S1-2. Pour the oil phase solution of the acyl chloride monomer into the reactor described in S1-1, and react at room temperature for 30-60 s to obtain the desalination separation membrane.

6. The method of claim 1, wherein the desalination separation membrane is prepared by the steps of: The preparation method of the 4,4',4'',4'''-methanetetramethyltetra(1,2-phenylenediamine) is as follows: S2-1. Dissolve 4,4',4'',4'''-methanetetraphenylamine in acetic acid and cool to 0 °C. Add acetic anhydride and stir at room temperature for 60 h to obtain a grayish-white suspension. Filter the resulting grayish-white suspension to obtain a grayish-white solid. Dissolve the grayish-white solid in DMF and pour the solution into ice water. Filter out the solid and wash to obtain tetra(4-N-acetaminophenyl)methane. S2-2. Cool a mixture of concentrated nitric acid and concentrated sulfuric acid to -10 °C, then add tetrakis(4-N-acetaminophenyl)methane, stir the solution at -10 °C for 10 min, stir at ambient temperature for 30 min, place it in ice water, filter out the precipitate and wash to obtain N,N',N'',N'''-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide; S2-3, N,N',N'',N'''-[methanetetramethyltetra(2-nitrobenzene-4,1-diyl)]tetraacetamide was dispersed in a mixed solution of ethanol and sodium hydroxide. The mixed solution was refluxed under heating and stirring for 2 hours, then cooled to room temperature and filtered to obtain 4,4',4'',4'''-methanetetramethyltetra(2-nitrobenzyl)amine. S2-4. 4,4',4'',4'''-methanetetrayltetra(2-nitroaniline) and tin(II) chloride dihydrate were dispersed in a mixed solution of ethanol and concentrated hydrochloric acid. The mixture was heated and stirred under reflux for 24 h. After cooling to room temperature, the precipitate was collected by filtration, washed with concentrated hydrochloric acid, dried under reduced pressure, washed with ethyl acetate, and recrystallized in dilute hydrochloric acid solution. Specifically, concentrated HCl solution was slowly added to boiling water containing 4,4',4'',4'''-methanetetrayltetra(phenyl-1,2-diamine) until the solution remained transparent. After cooling to room temperature, a white crystalline precipitate was formed. The precipitate was collected by filtration and dried to obtain pure 4,4',4'',4'''-methanetetrayltetra(phenyl-1,2-diamine).

7. The method of claim 1, wherein the desalination separation membrane is prepared by the steps of: The preparation method of the 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine is as follows: S3-1. Dissolve 2,2',7,7'-tetraammonium-9,9'-spirobisfluorene tetrachloride in acetic acid and cool to 0°C. Add acetic anhydride and stir the reaction at ambient temperature for 60 h to obtain a grayish-white suspension. After precipitation and filtration, a grayish-white solid is obtained. Dissolve the grayish-white solid in DMF and pour the solution into ice water. Filter out the solid and wash it with water to obtain 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene. S3-2. Cool a mixed solution of concentrated nitric acid and concentrated sulfuric acid to -10 °C, then add 2,2',7,7'-tetra(acetamido)-9,9'-spirobisfluorene. Stir the solution at -10 °C for 10 minutes, then stir at ambient temperature for 30 minutes to obtain an orange-red transparent solution. Place the orange-red solution in ice water, filter out the precipitate and wash with water to obtain 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene. S3-3. 2,2',7,7'-tetra(acetamido)-3,3',6,6'-tetranitro-9,9'-spirobisfluorene was dispersed in a mixed solution of ethanol and sodium hydroxide aqueous solution. The mixed solution was heated under reflux for 2 h with stirring, then cooled to room temperature, evaporated and concentrated, and filtered to obtain 2,2',7,7'-tetraamino-3,3',6,6'-tetranitro-9,9'-spirobisfluorene hydrogen chloride. S3-4. 2,2',7,7'-Tetraamino-3,3',6,6'-Tetranitro-9,9'-spirobisfluorene hydrogen chloride and tin(II) chloride dihydrate were dispersed in a mixed solution of ethanol and concentrated hydrochloric acid. The mixed solution was heated under reflux for 24 h with stirring. After cooling to room temperature, the precipitate was collected by filtration, washed with concentrated hydrochloric acid, dried under reduced pressure, washed with ethyl acetate, and recrystallized in dilute hydrochloric acid solution. Concentrated HCl solution was slowly added to boiling water containing 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine until the solution remained transparent. After cooling to room temperature, a crystalline precipitate was formed. The precipitate was collected by filtration and dried to obtain 9,9'-spirobis[fluorene]-2,2',3,3',6,6',7,7'-octaamine.

8. The desalination separation membrane prepared according to the method of any one of claims 1-7, wherein, The thickness of the desalination separation membrane is 20~100 nm.

9. A desalination separation membrane prepared according to any one of the methods of claims 1-7 or use of a desalination separation membrane according to claim 8, characterized in that, The desalination membrane is installed on a cross-flow separation device to achieve the separation of antibiotics and salts at room temperature, with an operating pressure of 2-6 bar.

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