A high-performance polyamide composite membrane and its preparation method and application

Abstract

The present invention discloses a high-performance polyamide composite membrane and a preparation method and application thereof, belonging to the technical field of water treatment membranes, and the method comprises: (1) performing negative charge modification on a porous support membrane to obtain a negatively charged support membrane; (2) successively depositing an aqueous phase solution containing polyamines and an oil phase solution containing polyacyl chlorides on the negatively charged support membrane, and preparing the high-performance polyamide composite membrane through interfacial polymerization reaction. The method of the present invention prepares a polyamide composite membrane on a negatively charged support membrane by a method of coordinated regulation of interfacial polymerization monomer adsorption and diffusion. The synergistic effect of the two not only changes the intrinsic physical structure of the polyamide separation layer, reduces the actual thickness of the separation layer, and reduces the water penetration resistance, but also affects the chemical properties of the surface of the separation layer, so that the surface of the separation layer carries more negative charges, strengthens the Donan repulsion effect of the membrane on charged particles, and realizes the simultaneous improvement of the water permeation flux and the interception rate of the polyamide composite membrane.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment membranes, and in particular to a high-performance polyamide composite membrane and a preparation method and application thereof. Background Art

[0002] Membrane treatment is a commonly used technology in the field of water treatment, which has the characteristics of simple operation, low cost and high efficiency. Membrane materials are the core of membrane treatment technology. Polyamide composite membrane materials dominate the water treatment membrane separation market. Polyamide composite membranes usually have a three-layer structure of polyamide separation layer, porous support layer and non-woven fabric substrate. Polyamide composite membranes have good chemical stability, good thermal stability and alkali resistance, low operating pressure and high desalination rate. Interfacial polymerization is the most commonly used method for preparing polyamide composite membranes in current industrial production. Although the existing polyamide composite membranes have shown good removal effects for antibiotics with larger molecular weight (Mw>700), the retention performance for medium and low molecular weight antibiotics still needs to be improved. Therefore, in view of the low content and small molecular size of medium and low molecular weight antibiotics, the structure and performance of the existing polyamide composite membranes still need to be optimized.

[0003] The Chinese patent document with publication number CN115301085A discloses a low-pressure nanofiltration membrane for treating mono / divalent salt and / or antibiotic wastewater and a preparation method thereof. The invention uses aminopiperidine as an aqueous phase monomer, loads it on the surface of a Kevlar base film, and then undergoes an interfacial polymerization reaction with trimesoyl chloride to construct an ultra-microporous piperidineamide membrane with a stable structure and high selectivity. The invention introduces a mesityl group that can increase the molecular chain length and an asymmetric amino group to promote hydrogen bonding between the molecular weights of the polyamide, thereby increasing the internal controllability of the selective layer, improving the internal free volume and maintaining high crosslinking, and increasing the controllability of the membrane pore size, thereby achieving effective separation of antibiotics under low-pressure operation.

[0004] The Chinese patent document with publication number CN114345140A discloses a method for preparing a high-performance composite nanofiltration membrane with an intermediate layer structure, comprising: preparing a casting solution, preparing an ultrafiltration or microfiltration base membrane by a phase inversion method; preparing a deposition solution using polyphenol compounds, oxidants and polyamine compounds; immersing the base membrane in the deposition solution to construct an intermediate layer; performing an interfacial polymerization reaction of piperazine and trimesoyl chloride on the membrane surface of the deposited intermediate layer; and obtaining a composite nanofiltration membrane with an intermediate layer structure after heat treatment. The composite nanofiltration membrane obtained by the invention has high flux and excellent retention performance, and has broad application prospects in the removal of antibiotics.

[0005] Most of the research, including the above-mentioned existing technologies, focuses on adjusting the parameters of the interfacial polymerization process (including reactive monomers, additives, reaction time, and thermal curing temperature, etc.) or introducing an intermediate layer to prepare high-performance polyamide composite membranes, but ignores the important role of the support layer in the membrane structure and performance regulation. With the deepening of the understanding of the interfacial polymerization process, it is found that the support layer not only plays a physical support role, but also has a huge impact on the formation and growth of the separation layer. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a high-performance polyamide composite membrane. The method is simple and efficient. The physical structure and chemical properties of the polyamide separation layer are regulated by adjusting the support layer. The prepared high-performance polyamide composite membrane has high water permeation flux, good ion selectivity and high antibiotic removal rate.

[0007] The specific technical solutions adopted are as follows:

[0008] A method for preparing a high-performance polyamide composite film, comprising:

[0009] (1) performing negative charge modification on the porous support membrane to obtain a negatively charged support membrane;

[0010] When the porous support membrane is a polyphenylene ether ultrafiltration membrane, a polystyrene ultrafiltration membrane or a polyetheretherketone ultrafiltration membrane, a sulfonation reaction is caused between the sulfonic acid substance and the porous support membrane to obtain a negatively charged support membrane;

[0011] When the porous support membrane is a polysulfone ultrafiltration membrane, a polyethersulfone ultrafiltration membrane, a polytetrafluoroethylene ultrafiltration membrane, a polypropylene ultrafiltration membrane, a polyethylene ultrafiltration membrane or a polyimide ultrafiltration membrane, the amino monomer and the porous support membrane are first subjected to an amination reaction to obtain an amination support membrane, and then the negatively charged monomer and the amination support membrane are subjected to a Michael addition reaction to obtain a negatively charged support membrane;

[0012] (2) The aqueous solution containing polyamine and the oily solution containing polyacyl chloride are successively deposited on the negatively charged support membrane, and the high-performance polyamide composite membrane is prepared through interfacial polymerization reaction.

[0013] The method of the present invention prepares a polyamide composite membrane on a negatively charged support membrane by a method of interfacial polymerization monomer adsorption and diffusion synergistic regulation. The negatively charged support membrane can generate an electrostatic interaction force with the aqueous phase monomer, which can not only increase the saturated adsorption amount of the support layer for the polyamine monomer, so that the adsorption amount of the support layer for the polyamine monomer can be changed in a larger range, increasing the interval of the interfacial polymerization reaction, but also inhibit the diffusion behavior of the positively charged aqueous phase monomer, so that it enters the oil phase solution at a slower diffusion rate. The synergistic effect of the two not only changes the intrinsic physical structure of the polyamide separation layer, reduces the actual thickness of the separation layer, and reduces the water penetration resistance, but also affects the chemical properties of the surface of the separation layer, so that the surface of the separation layer carries more negative charges, strengthens the Donnan repulsion effect of the membrane on charged particles, and achieves the simultaneous improvement of water permeation flux and interception rate.

[0014] Preferably, during the sulfonation reaction, the porous support membrane is immersed in a reaction solution containing a sulfonic acid substance for sulfonation reaction, and the sulfonic acid substance is at least one of chlorosulfonic acid, sulfur trioxide, trinitrobenzenesulfonic acid, nitrosulfuric acid, and trifluoromethanesulfonic acid.

[0015] More preferably, in the reaction solution containing sulfonic acid substances, the concentration of the sulfonic acid substances is 0.25-1.0 mol / L.

[0016] Further preferably, the reaction conditions of the sulfonation reaction are: temperature 30-60° C., time 0.5-2 h.

[0017] Preferably, during the amination reaction, the porous support membrane is immersed in a reaction solution containing an amino monomer for an amination reaction, wherein the amino monomer is at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine.

[0018] More preferably, in the reaction solution containing the amino monomer, the content of the amino monomer is 10-20 wt %.

[0019] Further preferably, the reaction conditions of the amination reaction are: temperature 90-160° C., time 24-48 h.

[0020] Preferably, during the Michael addition reaction, the amino support membrane is immersed in a reaction solution containing a negatively charged monomer to carry out a Michael addition reaction, wherein the negatively charged monomer is at least one of acrylic acid, methacrylic acid, propylene sulfonic acid, sodium methacrylate sulfonate, 2-acrylamide-2-methylpropane sulfonic acid, sodium acrylate, sodium methacrylate, sodium 2-acrylamide-2-methylpropane sulfonate, cis-acrylic phosphoric acid, and cis-acrylic sodium phosphate.

[0021] More preferably, in the reaction solution containing negatively charged monomers, the content of the negatively charged monomers is 0.5-2 wt %.

[0022] More preferably, the reaction conditions of the Michael addition reaction are: temperature 20-30° C., time 6-24 h.

[0023] The present invention performs negative charge modification on a conventional inert and uncharged porous support membrane, adopts a sulfonation reaction or an aminolysis-Michael addition two-step reaction, thereby in situ introducing negatively charged groups on the surface of the porous support membrane, thereby increasing the content of negatively charged groups on the membrane surface without significantly changing the physical structure and pore characteristics of the porous support membrane.

[0024] Preferably, in the aqueous phase solution, the aqueous phase monomer polyamine is at least one of piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, m-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, xylene diamine, ethylenediamine, propylenediamine, tris(2-aminoethyl)amine, 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, and 1,4-diaminocyclohexane.

[0025] Preferably, in the oil phase solution, the oil phase monomer polyacyl chloride is at least one of trimesoyl chloride, terephthaloyl chloride, phthaloyl chloride, pyromellitoyl chloride, malonyl chloride, glutaryl chloride, and fumaroyl chloride; and the solvent of the oil phase solution is at least one of n-hexane, cyclohexane, n-heptane, toluene, benzene, isopar G, isopar E, isopar H, isopar L, and isopar M.

[0026] More preferably, in the aqueous phase solution, the content of the polyamine is 0.05-2 wt %, and in the oil phase solution, the content of the oil phase monomer is 0.05-2 wt %.

[0027] Preferably, in step (2), the interfacial polymerization method is:

[0028] 1) pouring the aqueous solution containing the polyamine onto the surface of the negatively charged support membrane, and removing the excess liquid on the membrane surface after the adsorption time of the polyamine on the negatively charged support membrane reaches 0.5-200 minutes;

[0029] 2) pouring the oil phase solution containing polyacid chloride onto the surface of the membrane obtained in step 1), leaving it in contact for 0.5-5 minutes, and then removing excess liquid on the membrane surface;

[0030] 3) The membrane obtained in step 2) is subjected to heat treatment to obtain the high-performance polyamide composite membrane.

[0031] Preferably, in step 1), when the negatively charged support membrane adsorbs the polyamine, the ambient temperature is 20-30°C and the ambient humidity is 30-60% RH. In the above environment, the aqueous solution can be prevented from volatilizing, ensuring that the negatively charged support membrane fully adsorbs the aqueous monomer.

[0032] Further preferably, in step 3), the heat treatment conditions are 50-80° C., 10-30 min.

[0033] The invention also provides a high-performance polyamide composite membrane prepared by the preparation method of the high-performance polyamide composite membrane.

[0034] The high-performance polyamide composite membrane comprises a non-woven fabric layer, a negatively charged support layer and a polyamide separation layer, and the pure water flux is > 15 L·m -2 ·h -1 bar -1 The removal rate of emerging pollutants such as trace ofloxacin in municipal water supply is >95%.

[0035] The present invention also provides the application of the high-performance polyamide composite membrane in the field of water treatment, especially in the field of municipal water and drinking water treatment.

[0036] The present invention also provides a method for treating antibiotic wastewater, using the high-performance polyamide composite membrane. Preferably, the antibiotics include ofloxacin; in the antibiotic wastewater, the concentration of the antibiotics is 1-10 ppm.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The method of the present invention not only increases the saturated adsorption amount of the support layer for the polyamine monomer by synergistically regulating the adsorption amount and diffusion rate of the aqueous phase monomer during the interfacial polymerization process, but also utilizes the electrostatic interaction force generated between the negatively charged support membrane and the aqueous phase monomer, so that the adsorption amount of the support layer for the polyamine monomer can be changed in a larger range, increasing the interval of the interfacial polymerization reaction, but also inhibits the diffusion behavior of the positively charged aqueous phase monomer, so that it enters the oil phase solution at a slower diffusion rate. The synergistic effect of the two not only changes the intrinsic physical structure of the polyamide separation layer, reduces the actual thickness of the separation layer, and reduces the water penetration resistance, but also affects the chemical properties of the separation layer surface, so that the separation layer surface carries more negative charges. Representatively, at pH = 7, the zeta potential value of the separation layer surface prepared by the method of the present invention reaches -28.2±0.5mV, while the zeta potential value of the separation layer surface of the traditional membrane under the same conditions is -21.8±0.7mV. More negative charges strengthen the Donnan repulsion effect of the membrane on charged particles, thereby realizing the preparation of high-performance polyamide composite membranes. By using negatively charged support membranes, the control range of the structure and performance of polyamide composite membranes can be further expanded, and polyamide composite membranes with corresponding surface structures and chemical properties can be customized according to actual application needs.

[0039] (2) The method of the present invention has a high reproducibility, and the regulation process of interfacial polymerization is relatively simple, with low equipment requirements. It is highly practical and scalable in the preparation process of polyamide composite membranes. The high-performance polyamide composite membranes prepared have broad application prospects in the field of water treatment.

[0040] (3) The polyamide composite membrane provided by the present invention has excellent water permeation flux, monovalent / multivalent salt separation factor and trace antibiotic removal ability, and the pure water flux is greater than 15L·m -2 ·h -1 bar -1 The removal rate of antibiotics such as ofloxacin in municipal water supply is >95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a SEM image of the surface of the high-performance polyamide composite membrane prepared in Example 3.

[0042] Figure 2 This is a TEM image of the cross section of the high-performance polyamide composite membrane prepared in Example 3. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with the embodiments and drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0044] Example 1

[0045] A commercial polyphenylene ether ultrafiltration membrane is used as a porous support membrane. After the porous support membrane is fully cleaned, it is immersed in a 0.25 mol / L chlorosulfonic acid solution. The chlorosulfonic acid and the porous support membrane are sulfonated at 30°C for 0.5h and then removed. The membrane surface is then rinsed with deionized water to obtain a negatively charged support membrane containing sulfonic acid groups on the surface. After completing the above steps, an aqueous solution containing 0.05wt% piperazine is poured on the surface of the negatively charged support membrane. After the adsorption time reaches 0.5min (the ambient temperature is maintained at 20°C and the ambient humidity is 55-60%RH), the excess liquid on the membrane surface is removed; then, a normal hexane solution containing 0.05wt% trimesoyl chloride is poured onto the membrane surface. After the contact is allowed to stand for 0.5min, the excess liquid on the membrane surface is removed, and the high-performance polyamide composite membrane is obtained by heat treatment in a water bath at 50°C for 10min.

[0046] Example 2

[0047] A commercial polystyrene ultrafiltration membrane is used as a porous support membrane. After the porous support membrane is fully cleaned, it is immersed in a 1.0 mol / L chlorosulfonic acid solution. The chlorosulfonic acid and the porous support membrane are sulfonated at 60°C for 2 hours and then removed. The membrane surface is then rinsed with deionized water to obtain a negatively charged support membrane containing sulfonic acid groups on the surface. After completing the above steps, an aqueous solution containing 2wt% piperazine is poured on the surface of the negatively charged support membrane. After the adsorption time reaches 200min (the ambient temperature is maintained at 30°C and the ambient humidity is 30-35%RH), the excess liquid on the membrane surface is removed; then, a normal hexane solution containing 2wt% trimesoyl chloride is poured onto the membrane surface. After the contact is allowed to stand for 5min, the excess liquid on the membrane surface is removed, and the high-performance polyamide composite membrane is obtained by heat treatment in a water bath at 80°C for 30min.

[0048] Example 3

[0049] A commercial polyethersulfone ultrafiltration membrane is used as a porous support membrane, and the porous support membrane is immersed in an aqueous solution containing 10 wt% diethylenetriamine. The diethylenetriamine and the porous support membrane are subjected to an amination reaction at 90°C for 24 hours, and then the membrane is taken out and the membrane surface is rinsed with anhydrous ethanol and deionized water in turn to obtain an amination support membrane containing amino groups on the surface; subsequently, the amination support membrane is immersed in an aqueous solution containing 0.5 wt% methacrylic acid, and the methacrylic acid and the amination support membrane are subjected to constant temperature oscillation at 20°C for 6 hours to undergo a Michael addition reaction, and then the membrane is taken out and rinsed with deionized water. The membrane surface is poured with a negatively charged support membrane; after completing the above steps, an aqueous solution containing 0.05wt% piperazine is poured on the surface of the negatively charged support membrane, and after the adsorption time reaches 0.5min (the ambient temperature is maintained at 20°C and the ambient humidity is 35-40%RH), excess liquid on the membrane surface is removed; subsequently, an n-hexane solution containing 0.05wt% trimesoyl chloride is poured onto the membrane surface, and after the contact is allowed to stand for 0.5min, excess liquid on the membrane surface is removed, and heat-treated at 50°C for 10min to obtain the high-performance polyamide composite membrane.

[0050] Example 4

[0051] A commercial polyethersulfone ultrafiltration membrane was used as a porous support membrane, and the porous support membrane was immersed in an aqueous solution containing 20 wt% triethylenetetramine, and the triethylenetetramine and the porous support membrane were subjected to an amination reaction at 160°C for 48 hours, and then the membrane was taken out, and the membrane surface was rinsed with anhydrous ethanol and deionized water in turn to obtain an amination support membrane containing amino groups on the surface; subsequently, the amination support membrane was immersed in an aqueous solution containing 2 wt% 2-acrylamide-2-methylpropanesulfonic acid, and the 2-acrylamide-2-methylpropanesulfonic acid and the amination support membrane were subjected to a Michael addition reaction at 30°C for 2 hours. 4h, and after taking it out, rinse the membrane surface with deionized water to obtain a negatively charged support membrane; after completing the above steps, pour an aqueous solution containing 2wt% piperazine on the surface of the negatively charged support membrane, and after the adsorption time reaches 200min (the ambient temperature is maintained at 30°C, and the ambient humidity is 50-55%RH), remove the excess liquid on the membrane surface; then, pour an n-hexane solution containing 2wt% trimesoyl chloride onto the membrane surface, let it stand for 5min, remove the excess liquid on the membrane surface, and heat treat it at 80°C for 30min to obtain the high-performance polyamide composite membrane.

[0052] Comparative Example 1

[0053] Using a commercial polyethersulfone ultrafiltration membrane as the porous support membrane, an aqueous solution containing 0.05wt% piperazine was poured on the surface of the porous support membrane. After being in contact and standing for 1 minute, excess liquid on the membrane surface was removed. Subsequently, an n-hexane solution containing 0.05wt% trimesoyl chloride was poured onto the membrane surface. After being in contact and standing for 0.5min, excess liquid on the membrane surface was removed. The membrane was then heat treated at 50°C for 10min to obtain a polyamide membrane based on traditional interfacial polymerization.

[0054] Comparative Example 2

[0055] A commercial polyethersulfone ultrafiltration membrane is used as a porous support membrane, and the porous support membrane is immersed in an aqueous solution containing 10wt% diethylenetriamine. The diethylenetriamine and the porous support membrane are subjected to an amination reaction at 90°C for 24 hours, and then the membrane is removed, and the membrane surface is rinsed with anhydrous ethanol and deionized water in succession to obtain an amination support membrane containing amino groups on the surface; after completing the above steps, an aqueous solution containing 0.05wt% piperazine is poured on the surface of the negatively charged support membrane, and after the adsorption time reaches 0.5min (the ambient temperature is maintained at 20°C and the ambient humidity is 35-40%RH), the excess liquid on the membrane surface is removed; subsequently, a n-hexane solution containing 0.05wt% trimesoyl chloride is poured onto the membrane surface, and after the contact is allowed to stand for 0.5min, the excess liquid on the membrane surface is removed, and a heat treatment is performed at 50°C for 10min to obtain a polyamide composite membrane based on an amination support layer.

[0056] Sample analysis

[0057] The microscopic morphology of the high-performance polyamide composite membrane prepared in Example 3 was analyzed. The surface SEM results and cross-sectional TEM results were as follows: Figure 1 and Figure 2 As shown, the separation layer vesicle structure of the high-performance polyamide composite membrane prepared by the method of the present invention is more uniform, and the thickness of the separation layer is 34±3 nm, which is thinner than the thickness of the separation layer of Comparative Example 1 (62±5 nm).

[0058] The performance of the polyamide composite membranes prepared in Examples 1 to 4 and Comparative Examples 1 and 2 was tested at room temperature using a cross-flow flat-plate membrane performance evaluation device. The pure water flux of the product membranes, the retention rate of a 2000 ppm Na2SO4 aqueous solution, the retention rate of a 2000 ppm NaCl aqueous solution, and a 10 ppm ofloxacin aqueous solution were tested (the test temperature was 25°C and the pressure was 5 bar). The results are shown in Table 1.

[0059] Table 1 Performance test results of polyamide composite membranes prepared in Examples 1 to 4 and Comparative Examples 1 and 2

[0060]

[0061] As shown in Table 1, compared with the comparative example, the embodiment proves that the pure water flux of the polyamide composite membrane prepared by the method of the present invention is significantly improved. This is because the negatively charged support membrane increases the adsorption amount of the aqueous phase monomer and inhibits the further diffusion of the monomer into the oil phase region, thereby controlling the interfacial polymerization reaction interval at a relatively small level, resulting in a reduction in the thickness of the polyamide separation layer and an improvement in water permeability. In addition, the polyamide composite membrane prepared in the embodiment has a significantly improved ofloxacin removal rate and better ion selectivity. This is because the polyamide separation layer of the product membrane in the embodiment has more negatively charged groups than the surface of the comparative example, which makes the composite membrane in the embodiment have a stronger Donnan exclusion effect on antibiotics such as ofloxacin, thereby improving the removal of trace small molecule antibiotics by the membrane.

[0062] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a polyamide composite film, characterized in that: include: (1) negatively charging the porous support membrane to obtain a negatively charged support membrane; When the porous support membrane is a polyphenylene ether ultrafiltration membrane, a polystyrene ultrafiltration membrane or a polyetheretherketone ultrafiltration membrane, a sulfonation reaction is performed between the sulfonic acid substance and the porous support membrane to obtain a negatively charged support membrane; during the sulfonation reaction, the porous support membrane is immersed in a reaction solution containing a sulfonic acid substance to perform a sulfonation reaction, wherein the sulfonic acid substance is at least one of chlorosulfonic acid, sulfur trioxide, trinitrobenzenesulfonic acid, nitrosulfuric acid, and trifluoromethanesulfonic acid; in the reaction solution containing the sulfonic acid substance, the concentration of the sulfonic acid substance is 0.25-1.0 mol / L; the reaction conditions of the sulfonation reaction are: temperature 30-60°C, time 0.5-2 h; When the porous support membrane is a polysulfone ultrafiltration membrane, a polyethersulfone ultrafiltration membrane, a polytetrafluoroethylene ultrafiltration membrane, a polypropylene ultrafiltration membrane, a polyethylene ultrafiltration membrane or a polyimide ultrafiltration membrane, an amino monomer is firstly subjected to an amination reaction with the porous support membrane to obtain an amination support membrane, and then a negatively charged monomer is subjected to a Michael addition reaction with the amination support membrane to obtain a negatively charged support membrane; during the amination reaction, the porous support membrane is immersed in a reaction solution containing an amino monomer to carry out an amination reaction, and the amino monomer is ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenetetramine, At least one of pentamine, pentaethylene hexamine, and polyethyleneimine; during the Michael addition reaction, the amino support membrane is immersed in a reaction solution containing a negatively charged monomer to carry out a Michael addition reaction, wherein the negatively charged monomer is at least one of acrylic acid, methacrylic acid, propylene sulfonic acid, sodium methyl propylene sulfonate, 2-acrylamide-2-methylpropane sulfonic acid, sodium acrylate, sodium methacrylate, sodium 2-acrylamide-2-methylpropane sulfonate, cis-propylene phosphoric acid, and cis-propylene sodium phosphate; in the reaction solution containing the amino monomer, the content of the amino monomer is 10-20 wt%; the reaction conditions of the amination reaction are: temperature 90-160 ° C, time 24-48 h; in the reaction solution containing the negatively charged monomer, the content of the negatively charged monomer is 0.5-2 wt%; the reaction conditions of the Michael addition reaction are: temperature 20-30 ° C, time 6-24 h; (2) The aqueous solution containing polyamine and the oil solution containing polyacyl chloride are successively deposited on the negatively charged support membrane, and the polyamide composite membrane is prepared by interfacial polymerization reaction.

2. The method for preparing a polyamide composite membrane according to claim 1, characterized in that: In the aqueous phase solution, the polyamine is at least one of piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, m-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, xylene diamine, ethylenediamine, propylenediamine, tris(2-aminoethyl)amine, 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, and 1,4-diaminocyclohexane; in the oil phase solution, the polyacyl chloride is at least one of trimesoyl chloride, terephthaloyl chloride, phthaloyl chloride, pyromellitoyl chloride, malonyl chloride, glutaryl chloride, and fumaroyl chloride.

3. The method for preparing a polyamide composite membrane according to claim 1, characterized in that: In step (2), the interfacial polymerization method is: 1) Pour the aqueous solution containing polyamine onto the surface of the negatively charged support membrane, and remove excess liquid on the membrane surface after the adsorption time of the polyamine on the negatively charged support membrane reaches 0.5-200 min; 2) Pour the oil phase solution containing polyacyl chloride onto the membrane surface obtained in step 1), let it stand for 0.5-5 minutes, and then remove the excess liquid on the membrane surface; 3) The membrane obtained in step 2) is subjected to heat treatment to obtain the polyamide composite membrane.

4. A polyamide composite membrane prepared according to the method for preparing a polyamide composite membrane according to any one of claims 1 to 3.

5. Use of the polyamide composite membrane according to claim 4 in the field of water treatment.

6. A method for treating antibiotic wastewater, characterized in that: Use the polyamide composite membrane described in claim 4.

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