Composite membrane for synchronously removing composite pollutants in water as well as preparation method and application of composite membrane

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a composite membrane for synchronously removing composite pollutants in water as well as a preparation method and application of the composite membrane. According to the invention, the composite pollutants in water are lead and tetracycline composite pollutants in water, and the composite membrane is a CuCoFe-LDH / PES composite membrane which is prepared by using polyether sulfone, namely PES, as a membrane matrix, using hydrotalcite-like CuCoFe-LDH as a functional immobilization material, using acetone to disperse CuCoFe-LDH, and using a blending method. The CuCoFe-LDH / PES composite membrane provided by the invention has good anti-pollution performance and high water flux, and efficient and synchronous removal of lead and tetracycline can be realized aiming at the condition of combined pollution of heavy metal lead and antibiotic tetracycline in a water body.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to a composite membrane for simultaneously removing composite pollutants in water and a preparation method and application thereof. BACKGROUND

[0002] Due to the difficulty of being completely metabolized by organisms, antibiotics are often excreted in the form of original shape or active metabolites with animal feces and urine, so that there are high concentrations of antibiotic residues in wastewater from farms. Since they pose a serious threat to water ecological environment safety and human health, people have paid increasing attention to the risk of antibiotics. At the same time, heavy metals are often added to animal feed as additives to promote animal growth, which is also the reason why there is a hidden danger of heavy metal pollution in wastewater from farms. Heavy metals also have high toxicity and are difficult to degrade, and can accumulate in the aquatic ecosystem, seriously threatening environmental safety and human health. As new and old environmental pollutants, antibiotics and heavy metals are simultaneously present in wastewater from farms through the above routes, forming composite pollution and attracting widespread attention.

[0003] Compared with single pollutants, the combined pollution of heavy metals and antibiotics has higher water environmental risk, and due to the significant difference in physicochemical properties, the composite pollution is more complex. For antibiotic-heavy metal composite pollution, scholars at home and abroad have carried out a series of researches mainly based on adsorption and advanced oxidation technology. That is, through adsorption technology and advanced oxidation technology, the problems of heavy metal and antibiotic pollution in water are solved respectively. Compared with single functional materials, it is more advantageous to develop a treatment technology that can simultaneously remove the pollution risk of antibiotics and heavy metals.

[0004] However, at present, there is no composite membrane and its preparation method for simultaneously removing lead and tetracycline compound pollutants in water in the prior art. Patent application CN202510823835.5 provides a cobalt-aluminum-zinc hydrotalcite assembly film and its preparation method and application. The invention relates to a cobalt-aluminum-zinc hydrotalcite assembly film catalyst and its preparation method and application. The catalyst is composed of an assembly film and a cobalt-aluminum-zinc hydrotalcite; the molar ratio of Co:Al:Zn in the cobalt-aluminum-zinc hydrotalcite is 1:(1-2):(1-2), and the mass fraction of the cobalt-aluminum-zinc hydrotalcite in the assembly film catalyst is 35-55%. Through a specific vacuum-assisted flocculation assembly method, the characteristics of high specific surface area of the hydrotalcite material itself are maintained, and a large number of active sites are provided for catalytic reactions, adsorption separation and other processes. The preparation process of the catalyst includes preparation of CoAlZn-LDH and preparation of CoAlZn LDH assembly film. This process not only improves the catalytic efficiency, but also optimizes the mechanical strength and thermal stability of the catalyst by introducing the assembly film, so that the structure and performance can remain stable under harsh conditions; the assembly film can be used to remove antibiotics such as tetracycline in water. Patent application CN202011136624.8 discloses a one-step solvothermal method for preparing a carbon fiber@MAl hydrotalcite composite film and its application. The preparation process of the composite film is as follows: first, the carbon paper is pretreated, then the divalent metal salt, Al2(SO4)3.18H2O and urea are dissolved in a mixed solution of alcohol and water to obtain a hydrotalcite precursor; after stirring, it is transferred to a reaction kettle, carbon paper is added, and a composite film is prepared by solvothermal method. The invention improves the hydrophilicity of the carbon paper by adding alcohol, so that the MAl hydrotalcite can grow on the carbon fiber, improving the bonding strength between the carbon fiber and the MAl hydrotalcite, and improving the adsorption effect of the composite film on heavy metal ions. Under certain conditions, the adsorption capacity of Pb(II) is 11.5mg / g, the adsorption rate is 99.8%, and the residual concentration of Pb(II) in the solution after adsorption is 0.04mg / L. Invention patent CN201510833131.2 relates to a preparation method of a hydrotalcite composite material and its application in heavy metal wastewater. The invention uses a coprecipitation method, first prepares a nitrate or chloride aqueous solution A of divalent metal cation M 2+ , a nitrate or chloride aqueous solution B of trivalent metal cation M 3+ , and an aqueous solution C of heavy metal ion chelating agent organic salt dispersed therein. After aging, vacuum drying, crushing and sieving, a heavy metal ion chelating agent intercalated hydrotalcite is obtained. After mixing with PVA to form a film, an LDHs / PVA composite film is prepared. The composite film adsorption material is immersed in heavy metal wastewater containing Cu 2+ , Cd 2+ or Pb 2+ , and the adsorption rate can reach 92%. The preparation method described in the invention has mild preparation conditions, low cost and good application prospect.

[0005] However, the above-mentioned solutions are only used for adsorbing and removing heavy metal lead ions or organic matter tetracycline in wastewater. Therefore, there is still a need to provide a composite membrane for simultaneously removing lead and tetracycline composite pollutants in water and a preparation method thereof. SUMMARY

[0006] Layered double hydroxides (LDHs) are a kind of inorganic porous materials with a layered structure, which are composed of positively charged metal hydroxide main layers and exchangeable anions. As a material that performs well in removing heavy metal ions, most heavy metal ions can be enriched by electrostatic adsorption, some of which will precipitate on the surface of LDHs by combining with surface hydroxyl groups or interlayer anions. For the removal of antibiotics, advanced oxidation water treatment technology based on LDHs has been widely recognized. Due to its adjustable layered structure, which contains transition metal ions with variable valence characteristics, a large number of active oxygen species can be easily generated under the catalysis of LDHs with the help of oxidizing agents or external energy input, which can oxidize antibiotic molecules into small molecular products with lower toxicity or no toxicity, or even directly mineralize them into CO2 and H2O. Therefore, it is reasonable to develop a heavy metal and antibiotic composite pollution treatment technology based on bifunctional LDHs. Considering that direct addition of particulate LDHs can easily lead to the risk of secondary pollution, and separation and recovery are difficult, high molecular film immobilization technology is a wise choice to solve the above problems. By fixing LDHs on the membrane material, not only can the problem of composite pollution of heavy metals and antibiotics in water be solved, but also clean filtrate can be directly obtained, and there is no need to worry about the leakage and recovery of LDHs. Using the blending method as the best solution for LDHs composite membrane, the operation is simple and has good stability, which can simultaneously achieve efficient removal of heavy metals and antibiotic composite pollution in water.

[0007] The purpose of the present application is to provide a composite membrane for simultaneously removing composite pollutants in water and a preparation method and application, which solves the current problem of composite pollution of heavy metal lead and antibiotic tetracycline in water in the background art.

[0008] Therefore, the present application first provides a composite membrane for simultaneously removing composite pollutants in water, wherein the composite pollutants in water are heavy metal lead and antibiotic tetracycline composite pollutants, and the composite membrane is a CuCoFe-LDH / PES composite membrane prepared by using polyether sulfone (PES) as a membrane matrix, using CuCoFe-LDH as a functionalized immobilized material, dispersing CuCoFe-LDH with acetone, and using a blending method.

[0009] In a specific embodiment, N, N'-dimethylformamide, namely DMF, PES, polyvinylpyrrolidone, namely PVP, and acetone are mixed in proportion, heated and stirred for a period of time to prepare a PES membrane matrix solution; CuCoFe-LDH is added to acetone for dispersion to obtain a dispersion liquid, the dispersion liquid is mixed with the PES membrane matrix solution, heated and stirred, and then aged and defoamed to form a CuCoFe-LDH / PES casting solution; the casting solution is uniformly applied to the surface of a flat plate, and then the flat plate coated with the casting solution is immersed in ultrapure water for phase inversion to obtain a CuCoFe-LDH / PES composite membrane.

[0010] In a specific embodiment, the flat plate is a dry and flat glass plate.

[0011] In a specific embodiment, the CuCoFe-LDH is prepared by a coprecipitation method, which specifically includes dissolving Cu(NO3)2·3H2O, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O in deionized water to prepare a mixed solution A; dissolving NaOH and Na2CO3 in deionized water to prepare a mixed solution B; adding solution A and solution B into beakers containing ultrapure water, while stirring rapidly to ensure that the solutions are fully mixed; after the coprecipitation reaction is completed, sealing and standing for a period of time, filtering the precipitate, washing with alcohol and ultrapure water until neutral, drying, and grinding to obtain CuCoFe-LDH.

[0012] In a specific embodiment, in solution A, the molar ratio of Cu(NO3)2·3H2O, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O is 1:1-20:0.1-10, preferably 1:2-5:0.5-2; in solution B, the molar ratio of NaOH and Na2CO3 is 2-120:1, preferably 3-10:1.

[0013] In a specific embodiment, during the coprecipitation reaction process, the reaction temperature is maintained at 20-100℃, and the solution pH value is maintained at 7-9.

[0014] In a specific embodiment, during the preparation of the PES membrane matrix solution, the molar ratio of DMF, PES, PVP, and acetone is 2-8:1:0.05-1.5:0.05-1, preferably 3-6:1:0.3-1:0.3-1; and the heating and stirring reaction temperature in this step is 40-90℃, and the stirring time is 1-24h.

[0015] In a specific embodiment, the molar ratio of PES to CuCoFe-LDH is 1:0.05-2, preferably 1:0.5-2; and the reaction temperature of the heated stirring mixture in this step is 40-90 DEG C, and the time is 12-24 hours.

[0016] The application also provides the application of the composite membrane for synchronously removing the composite pollutants in water as described above or the composite membrane prepared by the preparation method as described above, the Pb(II) concentration of the composite pollutants being 10-300 mg / L, and the tetracycline concentration being 10-120 mg / L.

[0017] In a specific embodiment, the Pb(II) concentration of the composite pollutants is 20-100 mg / L, and the tetracycline concentration is 10-30 mg / L.

[0018] Compared with the prior art, the application has at least the following beneficial effects:

[0019] 1. The bifunctional CuCoFe-LDH / PES composite membrane material in the application exhibits excellent long-acting removal capacity for Pb(II) and tetracycline in water, and provides technical support for solving the problem of composite pollution of heavy metals and antibiotics in water. That is, the application first designs a bifunctional CuCoFe-LDH / PES composite membrane material, which can efficiently and synchronously treat the more common and more difficult to treat heavy metal-antibiotic composite pollution problem in the water environment.

[0020] 2. The hydrotalcite used in the CuCoFe-LDH / PES composite membrane material of the application is CuCoFe-LDH, in which the key two-variable valence metals Cu and Co are introduced, which is not only beneficial to the adsorption and complexation of Pb(II) on the surface of the composite membrane material, but also promotes the activation of O2 in air under normal temperature and pressure by strengthening the electron transfer of the two-variable valence metals, so that the CuCoFe-LDH / PES composite membrane produces reactive oxygen species to realize efficient degradation of tetracycline without the need for an external oxidant.

[0021] 3. The CuCoFe-LDH / PES composite membrane material is prepared by the blending-phase inversion method, the LDH is uniformly dispersed in the PES casting solution in the application, the blending membrane is formed by phase inversion, the LDH is embedded in the inside of the membrane material, the overall structure of the composite membrane is uniform and stable, and the LDH is not easy to fall off.

[0022] 4. The CuCoFe-LDH / PES composite membrane material prepared by this invention, through acetone pre-dispersion, effectively solves the problems of poor structural uniformity, low mechanical strength, difficulty in balancing antifouling performance and water flux, and unstable pollutant removal effect caused by nanoparticle agglomeration and low loading in conventional blending membrane preparation. This provides a technical reference for the preparation of LDH-based and polymer-based composite membrane materials. Specifically, this invention uses acetone to disperse CuCoFe-LDH, solving the problems of CuCoFe-LDH nanoparticle agglomeration or excessive coating by the membrane matrix, thereby improving the structural uniformity, stability, and active site utilization of the composite membrane.

[0023] 5. The membrane matrix of the CuCoFe-LDH / PES composite membrane of the present invention is PES, which is a hydrophobic polymer with high mechanical strength, good chemical stability, and resistance to acid and alkali corrosion and microorganisms. It is often used as an ideal matrix for composite membrane materials in continuous membrane separation experiments and applications. In contrast, the membrane matrix PVA used in the prior art is a hydrophilic polymer. Although it has good film-forming properties, its mechanical strength in the wet state is not high, it is easily water-soluble, and it has certain biocompatibility.

[0024] 6. This invention prepares a composite membrane material with both "adsorption" and "catalytic oxidation" functions, enabling continuous removal and separation of pollutants in water and directly obtaining clean filtrate. This invention avoids the problem of difficult membrane material recovery. The composite membrane described in this invention also possesses the ability to be recycled multiple times from typical catalysts and adsorbents. This invention is easier to integrate into modern water treatment processes for the advanced treatment of combined heavy metal and antibiotic pollution in water.

[0025] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The present invention will now be described in further detail. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative examples and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 This is a scanning electron microscope (SEM) image of the PES film in this invention;

[0028] Figure 2 This is a SEM image of the CuCoFe-LDH / PES composite membrane in this invention;

[0029] Figure 3 This is a diagram of the water contact angle (WCA) of the PES membrane in this invention;

[0030] Figure 4 This is the WCA diagram of the CuCoFe-LDH / PES composite membrane in this invention;

[0031] Figure 5 This is a comparison chart of the antifouling performance of PES membrane and CuCoFe-LDH / PES composite membrane in this invention;

[0032] Figure 6 This is a simulation diagram of the adsorption kinetics of Pb(II) on the PES membrane and CuCoFe-LDH / PES composite membrane in this invention;

[0033] Figure 7 This is a graph showing the catalytic oxidation degradation efficiency of tetracycline by the PES membrane and CuCoFe-LDH / PES composite membrane in this invention.

[0034] Figure 8 This is a graph showing the long-term cyclic adsorption performance of Pb(II) on the CuCoFe-LDH / PES composite membrane in this invention.

[0035] Figure 9 This is a graph showing the long-term cyclic catalytic oxidative degradation performance of tetracycline by the CuCoFe-LDH / PES composite membrane in this invention.

[0036] Figure 10 This is a graph showing the change in flux of the CuCoFe-LDH / PES composite membrane in this invention with the number of cycles. Detailed Implementation

[0037] The embodiments of the present invention will be described in detail below. The specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0038] This invention provides a composite membrane for the simultaneous removal of lead and tetracycline contaminants from water, its preparation method, and its application. The composite membrane uses PES as the membrane matrix and CuCoFe-LDH as the functionalized immobilizing material, and is prepared by a blending method to obtain a CuCoFe-LDH / PES composite membrane material.

[0039] Specifically, the steps include the following:

[0040] S1. Dissolve Cu(NO3)2·3H2O, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O in deionized water to prepare mixed solution A. The molar ratio of Cu(NO3)2·3H2O, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O used is 1:1~20:0.1~10. Dissolve NaOH and Na2CO3 in deionized water to prepare mixed solution B. The molar ratio of NaOH and Na2CO3 used is 2~120:1.

[0041] S2. Add solutions A and B separately to beakers containing ultrapure water, stirring rapidly to ensure thorough mixing. Maintain the reaction conditions at a temperature of 20–100°C and a pH of 7–9. After the co-precipitation reaction is complete, seal and allow to stand for a period of time. Filter the precipitate, wash with alcohol and ultrapure water until neutral, dry, and grind to obtain CuCoFe-LDH.

[0042] S3. Mix N,N'-dimethylformamide (DMF), PES, polyvinylpyrrolidone (PVP), and acetone in a ratio of 2~8:1:0.05~1.5:0.05~1. Heat and stir for a period of time, at a temperature of 40~90℃, for 1~24 hours. Prepare the PES membrane matrix solution.

[0043] S4. Disperse CuCoFe-LDH in acetone, then pour in the PES membrane matrix solution prepared in step S3. The molar ratio of PES to CuCoFe-LDH is 1:0.05~2. Heat and stir to mix, then age and degas to form a CuCoFe-LDH / PES casting solution. The reaction temperature is 40~90℃, and the time is 12~24 h. Evenly coat the casting solution onto a dry and flat glass plate surface, then immerse the glass plate in ultrapure water to undergo phase inversion, thus obtaining the CuCoFe-LDH / PES composite membrane.

[0044] The present invention also provides an application of the composite membrane material prepared by the preparation method described above, which is used to simultaneously remove lead and tetracycline composite pollutants from water, wherein the concentration of Pb(II) in the composite pollutants is 10~300 mg / L and the concentration of tetracycline is 10~120 mg / L.

[0045] Example 1

[0046] This embodiment describes a method for preparing a CuCoFe-LDH / PES composite membrane, including the following steps:

[0047] 1) Dissolve Cu(NO3)2·3H2O, Co(NO3)2·6H2O, and Fe(NO3)3·9H2O in deionized water in a molar ratio of 1:3:1 to prepare mixed solution A. Dissolve NaOH and Na2CO3 completely in a molar ratio of 6:1 to prepare mixed solution B.

[0048] 2) Add solutions A and B to beakers containing ultrapure water respectively, and stir rapidly to ensure thorough mixing. The reaction conditions are: temperature maintained at 70℃, pH value maintained at 8±0.2, and reaction time of 18h to obtain CuCoFe-LDH.

[0049] 3) N,N'-dimethylformamide (DMF), polyethersulfone (PES), polyvinylpyrrolidone (PVP), and acetone were mixed in a molar ratio of 3-5:1:0.67:0.67 and stirred at 80°C for 12 hours to prepare a PES membrane matrix solution. The PES membrane matrix solution was then uniformly coated onto a dry, flat glass plate. The glass plate was then immersed in ultrapure water to undergo a phase inversion, yielding a PES membrane for comparative observation. Figure 1 As shown.

[0050] 4) Disperse CuCoFe-LDH in acetone, then pour in a PES membrane matrix solution. The molar ratio of PES to CuCoFe-LDH is 1:1. Heat and stir at 60℃ for 18 h. After aging and degassing, a CuCoFe-LDH / PES casting solution is formed. The casting solution is evenly coated onto a dry, flat glass plate surface, and then the glass plate is immersed in ultrapure water to undergo phase inversion, thus obtaining the CuCoFe-LDH / PES composite membrane. Figure 2 As shown.

[0051] Example 2

[0052] Water contact angle (WAC) tests were performed on the PES membrane and the CuCoFe-LDH / PES composite membrane. The results showed that the WACs of the PES membrane and the CuCoFe-LDH / PES composite membrane were 128° and 70°, respectively. Figure 3 , Figure 4 As shown, WAC represents the surface hydrophilicity / hydrophobicity of the membrane; the stronger the hydrophilicity, the smaller the WAC value. Therefore, with the immobilization of CuCoFe-LDH, the hydrophilicity of the CuCoFe-LDH / PES composite membrane is significantly improved, which is more conducive to its contact with pollutants in the water.

[0053] Example 3

[0054] Prepare bovine serum albumin solution by placing a PES membrane and a CuCoFe-LDH / PES composite membrane in a low-pressure flat-panel membrane filtration device, with an effective membrane area of ​​2 cm². 2 The water flux and antifouling performance of the membranes were tested under a constant transmembrane pressure (0.1 MPa). The results showed that the initial water flux of the PES membrane and the CuCoFe-LDH / PES composite membrane were 1525 L·m⁻¹, respectively. -2 ·h -1 ·bar -1 and 619 L·m -2 ·h -1 ·bar -1 After two cycles, the flux recovery rates of the PES membrane and the CuCoFe-LDH / PES composite membrane were 50% and 70%, respectively.Figure 5 As shown. From Figure 5 It is evident that, compared to PES membranes, although CuCoFe-LDH / PES composite membranes exhibit some water flux loss, their flux recovery rate is significantly improved, indicating that CuCoFe-LDH / PES composite membranes have better antifouling performance and achieve a good balance between flux and antifouling properties. Figure 5 The horizontal axis represents time in minutes, and the vertical axis represents water flux in L·m. -2 ·h -1 ·bar -1 Since the pressure in this embodiment is 1 bar, the unit can also be written as L·m. -2 ·h -1 .

[0055] Example 4

[0056] Prepare 50 mL of a combined contamination solution of 50 mg / L Pb(II) and 20 mg / L tetracycline. Place the PES membrane and the CuCoFe-LDH / PES composite membrane in these solutions for shake-flask experiments. The results show that the maximum adsorption capacities of the PES membrane and the CuCoFe-LDH / PES composite membrane for Pb(II) are 11 mg / g and 128 mg / g, respectively. Figure 6 As shown; the removal rates for tetracycline were 8% and 89%, respectively. Figure 7 As shown, the CuCoFe-LDH / PES composite membrane exhibits excellent removal efficiency for combined pollution from heavy metal lead and antibiotic tetracycline. Figure 6 The solid line and the short dashed line represent the pseudo-first-order kinetic model and the pseudo-second-order kinetic model of adsorption, respectively.

[0057] Example 5

[0058] Prepare a combined contamination solution of 50 mg / L Pb(II) and 20 mg / L tetracycline. Place the CuCoFe-LDH / PES composite membrane in a low-pressure flat-panel membrane filtration device with an effective membrane area of ​​2 cm². 2 A long-term cyclic experiment was conducted for 1100 min under constant transmembrane pressure (0.1 MPa), with the 1100 min period divided into 14 cycles. The experimental results show that the CuCoFe-LDH / PES composite membrane achieves a Pb(II) removal efficiency of 30 L / m³. 2 ,like Figure 8 As shown; Figure 8 The horizontal axis represents the standardized volume, in L / m³. 2 The vertical axis represents lead content, in ppm; the removal efficiency for tetracycline has consistently remained above 70%, such as... Figure 9As shown, the water flux was measured after 14 cycles. Even after 14 cycles, the water flux of the CuCoFe-LDH / PES composite membrane remained at 260 L·m. -2 ·h -1 ·bar -1 Left and right, such as Figure 10 As shown. Figure 10 The horizontal axis represents circulation time, and the vertical axis represents water flux. In summary, the CuCoFe-LDH / PES composite membrane exhibits excellent long-term removal performance for Pb(II) and tetracycline combined pollution.

[0059] In summary, this invention belongs to the field of water treatment technology, specifically relating to a composite membrane for the simultaneous removal of multiple pollutants in water, its preparation method, and its application. In this invention, the multiple pollutants in the water are lead and tetracycline. The composite membrane is a CuCoFe-LDH / PES composite membrane prepared by a blending method using polyethersulfone (PES) as the membrane matrix, CuCoFe-LDH (a type of hydrotalcite) as the functionalized immobilizing material, and CuCoFe-LDH dispersed in acetone. The CuCoFe-LDH / PES composite membrane provided by this invention possesses both excellent antifouling properties and high water flux, enabling efficient simultaneous removal of lead and tetracycline from water containing multiple pollutants.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite membrane for simultaneous removal of composite pollutants in water, characterized by, The composite pollutants in the water are lead and tetracycline composite pollutants, and the composite membrane is a CuCoFe-LDH / PES composite membrane prepared by using polyether sulfone (PES) as a membrane matrix and CuCoFe-LDH as a functionalized solid support material, dispersing CuCoFe-LDH in acetone, and preparing the CuCoFe-LDH / PES composite membrane by a blending method.

2. A method of preparing the composite film of claim 1, wherein DMF, PES, PVP and acetone are mixed in a certain proportion, heated and stirred for a period of time to prepare a PES membrane matrix solution; CuCoFe-LDH is added to acetone for dispersion to obtain a dispersion liquid, and the dispersion liquid is mixed with the PES membrane matrix solution, heated and stirred, and then aged and defoamed to form a CuCoFe-LDH / PES casting solution; the casting solution is uniformly applied to the surface of a flat plate, and then the flat plate coated with the casting solution is immersed in ultrapure water for phase inversion to obtain a CuCoFe-LDH / PES composite membrane.

3. The production method according to claim 2, characterized by, The flat plate is a dry and flat glass plate.

4. The production method according to claim 2, characterized by, The CuCoFe-LDH is prepared by a coprecipitation method, and specifically includes the following steps: Cu(NO3)2·3H2O, Co(NO3)2·6H2O and Fe(NO3)3·9H2O are dissolved in deionized water to prepare a mixed solution A; NaOH and Na2CO3 are dissolved in deionized water to prepare a mixed solution B; solutions A and B are added to beakers containing ultrapure water, and stirred rapidly at the same time to ensure that the solutions are fully mixed; after the coprecipitation reaction is completed, the mixture is sealed and left to stand for a period of time, the precipitate is filtered, washed with alcohol and ultrapure water until neutral, dried and ground to obtain CuCoFe-LDH.

5. The production method according to claim 4, characterized by, In solution A, the molar ratio of Cu(NO3)2·3H2O, Co(NO3)2·6H2O and Fe(NO3)3·9H2O is 1:1-20:0.1-10, and preferably 1:2-5:0.5-2; in solution B, the molar ratio of NaOH and Na2CO3 is 2-120:1, and preferably 3-10:

1.

6. The preparation method according to claim 4, characterized in that, During the coprecipitation reaction process, the reaction temperature is kept at 20-100°C, and the pH value of the solution is kept at 7-9.

7. The method of any one of claims 2-6, wherein, In the process of preparing the PES membrane matrix solution, the molar ratio of DMF, PES, PVP and acetone is 2-8:1:0.05-1.5:0.05-1, and preferably 3-6:1:0.3-1:0.3-1; and the heating and stirring reaction temperature in this step is 40-90°C, and the stirring time is 1-24h.

8. The method of any one of claims 2-6, wherein, The molar ratio of PES to CuCoFe-LDH is 1:0.05-2, and preferably 1:0.5-2; and the heating and stirring reaction temperature in this step is 40-90°C, and the time is 12-24h.

9. Use of the composite membrane for simultaneous removal of complex pollutants from water according to claim 1 or prepared by the method according to any one of claims 2 to 8, characterized in that, The concentration of Pb(II) in the composite pollutants is 10-300 mg / L, and the concentration of tetracycline is 10-120 mg / L.

10. Use according to claim 9, characterized in that, The concentration of Pb(II) in the composite pollutants is 20-100 mg / L, and the concentration of tetracycline is 10-30 mg / L.

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