Preparation method of anti-pollution membrane based on amphoteric dynamic supramolecules

Abstract

The invention discloses a preparation method of an anti-pollution membrane based on amphoteric dynamic supramolecules, and belongs to the technical field of preparation of water treatment membranes. The method comprises the following steps: preparing a high-flux base membrane by a non-solvent induced phase separation method; the preparation method comprises the following steps: preparing an amphoteric supramolecule with a line-through-ring quasi-polyrotaxane structure through a solvent-induced self-assembly method; based on free radical polymerization reaction, amphoteric dynamic supramolecules are grafted to the surface of the base membrane to form an anti-pollution layer. A supramolecular structure formed by cyclodextrin and polydimethylsiloxane is combined with a hydrophilic and low-surface-energy micro-area synergistic anti-pollution mechanism, so that the anti-pollution performance and the water flux of the membrane are improved. The dynamic supramolecular structure has good anti-pollution performance, adapts to different flow velocity and temperature conditions, is high in flux and low in attenuation rate, and is suitable for various water treatment processes. The preparation process is simple, raw materials are easy to obtain, and the cost is low; the membrane flux is obviously improved, the anti-pollution capacity is enhanced, and the performance is easy to recover through simple cleaning; good adaptability is realized in a wide temperature range and a wide pH (Potential of Hydrogen) range.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of water treatment membranes, and in particular relates to a method for preparing an anti-pollution membrane based on amphiphilic dynamic supramolecules. Background Art

[0002] In the development of water treatment technology, membrane fouling has always been one of the main problems limiting membrane performance and service life. In order to improve the anti-fouling performance of water treatment membranes, hydrophilic modification has become a widely adopted strategy. The surface of the hydrophilic membrane can preferentially adsorb water molecules to form a protective hydration film, thereby effectively preventing the direct attachment of pollutants. This anti-fouling mechanism is called the "pollution impedance mechanism" and has a certain effect in many water treatment applications. However, although the hydrophilic membrane can prevent the adhesion of pollutants in the early stage, for those pollutants that have been deformed and adhered to the membrane surface, hydrophilic modification cannot completely prevent the accumulation of pollutants, and long-term use will still lead to a decline in membrane performance.

[0003] In order to further improve the anti-fouling performance of the membrane, heterogeneous membranes have gradually attracted attention. This type of membrane combines the two mechanisms of pollution resistance and pollution release by constructing heterogeneous micro-regions with hydrophilicity and low surface energy on the membrane surface. The hydrophilic micro-regions can prevent the initial attachment of pollutants, while the low surface energy micro-regions promote the release of pollutants under external disturbance conditions by reducing the adhesion between pollutants and the membrane surface. This synergistic anti-fouling mechanism can significantly improve the pollution resistance of the membrane in actual operation, especially when some pollutants have already attached, the low surface energy micro-regions can effectively reduce the residual pollutants. However, the application of heterogeneous membranes in water treatment also faces some challenges, including that the mechanism usually relies on strong tangential flow, while the low surface energy hydrophobic micro-regions may increase the water flow resistance of the membrane and affect the water flux of the membrane; therefore, improving the basic flux of heterogeneous anti-fouling membranes and solving the dependence of heterogeneous membranes on tangential flow velocity are the research and development focuses in this field, in order to prepare high-quality water treatment membranes with low cost, high flux and anti-fouling characteristics, and solve the problem of easy pollution and performance degradation of traditional membranes in water treatment. Summary of the invention

[0004] The direct purpose of the present invention is to improve the basic flux of heterogeneous anti-fouling membranes and solve the problem of heterogeneous membranes' dependence on tangential flow velocity. The fundamental purpose is to prepare high-quality water treatment membranes with low cost, high flux and anti-fouling properties, thereby providing a method for preparing anti-fouling membranes based on amphiphilic dynamic supramolecules.

[0005] A method for preparing an anti-fouling membrane based on amphiphilic dynamic supramolecules is carried out according to the following steps:

[0006] 1. Preparation of high-flux polyethersulfone-based membrane:

[0007] Polyethersulfone, polyvinylpyrrolidone, Pluronic F127 and dimethylformamide were mixed in a mass ratio of 14:7:7:72 to form a casting solution, and then stirred at 70°C for 4 hours, and allowed to stand at 70°C for 4 hours to remove bubbles. After the casting solution was naturally cooled to 25°C, it was coated on a glass plate to form a 250 μm thick liquid film, and then immersed in a special coagulation bath for 5 minutes to obtain a base film, and then immersed in deionized water for ≥12 hours for standby use;

[0008] 2. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecular:

[0009] Adding polydimethylsiloxane to a saturated cyclodextrin solution, performing ultrasonication, shaking and standing in sequence, then precipitating the product, and then extracting and washing with cyclohexane, washing with distilled water and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, and then preparing a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion;

[0010] 3. Preparation of hydrophilic-low surface energy dynamic anti-pollution layer:

[0011] The base film prepared in step 1 is coated with a desalted aqueous solution of glycidyl methacrylate, then irradiated with ultraviolet light under nitrogen protection, and then washed with deionized water to obtain a membrane A;

[0012] At room temperature, the membrane A is immersed in the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, taken out and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, that is, an anti-fouling membrane based on amphoteric dynamic supramolecules, thereby completing the preparation method;

[0013] The product in step 2 is precipitated: the precipitation method is adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, 60% to 90% by weight of dimethylformamide is removed by rotary evaporation, and then an equal amount of distilled water is added to induce the precipitation of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane; when the cyclodextrin is γ-cyclodextrin, γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane will spontaneously form a gel-like precipitate;

[0014] The cyclodextrin / polydimethylsiloxane pseudopolyrotaxane obtained in step 2, wherein the molar ratio of cyclodextrin to polydimethylsiloxane depends on the type of cyclodextrin and the mass addition ratio of cyclodextrin to polydimethylsiloxane;

[0015] When the cyclodextrin is β-cyclodextrin, the mass addition ratio of β-cyclodextrin to polydimethylsiloxane is (2.24-10.10):1, and the molar ratio of β-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.53):1;

[0016] When the cyclodextrin is γ-cyclodextrin, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is (2.45-13.78):1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.67):1.

[0017] Furthermore, the special coagulation bath in step 1 is composed of water and dimethylformamide in a mass ratio of (1:8) to (8:1).

[0018] Furthermore, the cyclodextrin in step 2 is β-cyclodextrin or γ-cyclodextrin; the terminal group of the polydimethylsiloxane is aminopropyl, and its molecular weight is 1000-5000Da.

[0019] Furthermore, in the saturated cyclodextrin solution in step 2, the solvent used is compatible with the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the solvent is dimethylformamide; when the cyclodextrin is γ-cyclodextrin, the solvent is water.

[0020] Furthermore, the ultrasound, shaking and standing parameters in step 2 are all adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the ultrasound power is 500-1500W, the time is 5-15min, the shaking rate is 50-100r / min, the time is 5-10d, and the standing time is 2d; when the cyclodextrin is γ-cyclodextrin, the ultrasound power is 200-600W, the time is 3-9min, the shaking rate is 50-100r / min, the time is 10-30h, and the standing time is 5-8h.

[0021] Furthermore, in step 2, a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion is prepared: the solute concentration in the dispersion is 1 to 3 g / L, the solvent is dimethylformamide and distilled water, and the volume ratio of dimethylformamide to distilled water is (2:1) to (1:2); preparation of the dispersion: dissolve the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane in dimethylformamide, and then add distilled water to ensure effective dispersion.

[0022] Furthermore, the mass concentration of the glycidyl methacrylate aqueous solution in step 3 is 1% to 3%, and the coating amount is 100 μl / cm 2 .

[0023] Furthermore, the amount of the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion in step 3 is 25 ml / cm 2 .

[0024] Furthermore, the ultraviolet irradiation in step 3: the ultraviolet intensity is 3 to 8 mW / cm 2 The irradiation time is 5 to 15 minutes.

[0025] Furthermore, the fluorescein-4-isothiocyanate solution in step 3 has a concentration of 2.5 to 7.5 mg / mL and a dosage of 1.5 to 3.5 mL / cm 2 .

[0026] Furthermore, the anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in step 3 is immersed in deionized water for 24 hours, and the water is replaced every 8 hours for standby use.

[0027] The anti-pollution membrane based on the amphiphilic dynamic supramolecular prepared in the present invention is an anti-pollution membrane based on the dynamic properties of heterogeneous supramolecular molecules, which combines the hydrophilic-low surface energy synergistic anti-pollution mechanism of heterogeneous membranes with supramolecular dynamic properties for the first time. Compared with conventional heterogeneous membranes, the basic flux is higher, and the dependence on the tangential water flow velocity is small, and excellent anti-pollution ability can be maintained in a weakly disturbed environment; compared with existing supramolecular membranes, the host-guest interaction force of the amphiphilic supramolecular membranes is lower, the activity is stronger, and with the help of the synergistic anti-pollution mechanism, the anti-pollution ability is improved stepwise.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) The raw materials used in the present invention are easily available and inexpensive, and can be prepared at room temperature without the need for atmosphere protection. The conventional membrane production line of phase inversion preparation-surface coating modification can be used to prepare the anti-pollution membrane of the amphoteric dynamic supramolecular.

[0030] (2) Compared with conventional heterogeneous membranes, the membrane flux is increased by 2 to 4 times. Under weak tangential flow conditions, the anti-fouling membrane flux attenuation rate of the amphiphilic dynamic supramolecular membrane is reduced by 40 to 65%. Under strong tangential flow conditions, the membrane flux attenuation rate is reduced by 25 to 35%. Simple hydraulic flushing can restore nearly 100% of the flux.

[0031] (3) The anti-fouling ability of the amphoteric dynamic supramolecular anti-fouling membrane increases with the increase of temperature, which can offset the increase of membrane fouling tendency caused by the increase of temperature to a certain extent, and has a good applicable temperature range (5-50℃).

[0032] (4) The anti-pollution membrane of the amphiphilic dynamic supramolecular membrane performed well in the pH range of 3 to 11, and alkaline conditions could enhance the interaction between cyclodextrin and water molecules, which was conducive to further improving the anti-pollution ability.

[0033] (5) The high flux, high adaptability and low maintenance of the anti-fouling membrane of the amphiphilic dynamic supramolecular membrane are suitable for a variety of water treatment processes, including deep treatment of drinking water, multi-stage treatment and reuse of sewage, etc.

[0034] The invention is suitable for the preparation of anti-pollution membrane based on amphoteric dynamic supramolecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figures 1 to 4They are respectively the flux data graphs of Examples 1 to 9 and the comparative example at temperatures of 5°C, 20°C, 35°C, 50°C and a pressure of 1.0 bar;

[0036] Figure 5 It is a bovine serum albumin (BSA) retention rate data graph of Examples 1 to 9 and the comparative example; wherein the BSA concentration in the feed is 1 g / L, the environment is neutral, the temperature is 20° C., and the stirring rate is 60 rpm.

[0037] Figure 6 It is a data graph of the anti-pollution ability of Examples 1 to 9 and the comparative example with BSA as the simulated pollutant; wherein the basic water flux test time is 15 minutes, the sewage treatment flux test time is 30 minutes, the cleaning time is 15 minutes, the water flux test time after cleaning is 15 minutes, the neutral environment, the temperature is 20°C, the operating stirring rate is 60rpm, and the cleaning stirring rate is 480rpm; the flux decay rate (FDR) is (basic water flux-sewage treatment flux) / basic water flux, and the flux recovery rate (FRR) is the water flux after cleaning / basic water flux;

[0038] Figure 7 , 8 9 are respectively the anti-pollution ability data graphs of Examples 3 and 6 with BSA as the simulated pollutant in different pH environments, different stirring rate environments and different temperature environments;

[0039] Fig.10 and 11 They are respectively the anti-pollution ability data graphs of Examples 3 and 6 for separating different simulated pollutants; wherein the simulated pollutants include BSA, emulsified hexadecane, sodium alginate (SA), yeast, and fulvic acid (HA), and the concentration is 1 g / L, and the hexadecane emulsion additionally contains 0.1 g / L of sodium dodecyl sulfate; the basic water flux test time is 15 min, the sewage treatment time is 30 min, the cleaning time is 15 min, and the water flux test time after cleaning is 15 min, which is repeated 5 times, and the basic water flux in the second cycle is the water flux after cleaning in the first cycle, the environment is neutral, the temperature is 20°C, the operating stirring rate is 60 rpm, and the cleaning stirring rate is 480 rpm. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any combination of the specific implementation modes.

[0041] Specific implementation method 1: This implementation method is a method for preparing an anti-pollution membrane based on amphoteric dynamic supramolecules, which is carried out in the following steps:

[0042] 1. Preparation of high-flux polyethersulfone-based membrane:

[0043] Polyethersulfone, polyvinylpyrrolidone, Pluronic F127 and dimethylformamide were mixed in a mass ratio of 14:7:7:72 to form a casting solution, and then stirred at 70°C for 4 hours, and allowed to stand at 70°C for 4 hours to remove bubbles. After the casting solution was naturally cooled to 25°C, it was coated on a glass plate to form a 250 μm thick liquid film, and then immersed in a special coagulation bath for 5 minutes to obtain a base film, and then immersed in deionized water for ≥12 hours for standby use;

[0044] 2. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecular:

[0045] Adding polydimethylsiloxane to a saturated cyclodextrin solution, performing ultrasonication, shaking and standing in sequence, then precipitating the product, and then extracting and washing with cyclohexane, washing with distilled water and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, and then preparing a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion;

[0046] 3. Preparation of hydrophilic-low surface energy dynamic anti-pollution layer:

[0047] The base film prepared in step 1 is coated with a desalted aqueous solution of glycidyl methacrylate, then irradiated with ultraviolet light under nitrogen protection, and then washed with deionized water to obtain a membrane A;

[0048] At room temperature, the membrane A is immersed in the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, taken out and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, that is, an anti-fouling membrane based on amphoteric dynamic supramolecules, thereby completing the preparation method;

[0049] The product in step 2 is precipitated: the precipitation method is adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, 60% to 90% by weight of dimethylformamide is removed by rotary evaporation, and then an equal amount of distilled water is added to induce the precipitation of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane; when the cyclodextrin is γ-cyclodextrin, γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane will spontaneously form a gel-like precipitate;

[0050] The cyclodextrin / polydimethylsiloxane pseudopolyrotaxane obtained in step 2, wherein the molar ratio of cyclodextrin to polydimethylsiloxane depends on the type of cyclodextrin and the mass addition ratio of cyclodextrin to polydimethylsiloxane;

[0051] When the cyclodextrin is β-cyclodextrin, the mass addition ratio of β-cyclodextrin to polydimethylsiloxane is (2.24-10.10):1, and the molar ratio of β-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.53):1;

[0052] When the cyclodextrin is γ-cyclodextrin, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is (2.45-13.78):1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.67):1.

[0053] In step 1 of this embodiment, the high-flux polyethersulfone-based membrane is prepared by combining non-solvent-induced phase separation and surface segregation methods.

[0054] The base membrane obtained in step 1 of this embodiment has an ultrafiltration-grade pore size, and its porosity is 10% to 50% higher than that of conventional ultrafiltration membranes.

[0055] The hydrophilic-low surface energy amphiphilic dynamic supramolecule obtained in step 1 of this embodiment is a "line-through-ring" pseudo-polyrotaxane structure, in which cyclodextrin is a hydrophilic ring-shaped main body and polydimethylsiloxane is a low surface energy linear main body.

[0056] In step 2 of this embodiment, the hydrophilic-low surface energy amphiphilic dynamic supramolecule is prepared by a solvent-induced self-assembly method.

[0057] The purpose of ultraviolet irradiation in step three of this embodiment is to initiate free radical polymerization and graft glycidyl methacrylate onto the base film.

[0058] The purpose of the ionized water washing in step three of this embodiment is to remove the unreacted glycidyl methacrylate on the base film.

[0059] The soaking described in step three of this embodiment: during the soaking in the cyclodextrin / polydimethylsiloxane pseudo-polyrotaxane dispersion, the terminal amino group of the polydimethylsiloxane reacts with the epoxy group of glycidyl methacrylate, so that most of the pseudo-polyrotaxanes are double-end grafted to the polyglycidyl methacrylate to form a "clothes rod" structure, and are converted into polyrotaxanes due to the end blocking; during the soaking in the fluorescein-4-isothiocyanate solution, the residual amino groups are blocked, so that almost all the pseudo-polyrotaxanes are converted into polyrotaxanes, and the cyclodextrin / polydimethylsiloxane polyrotaxane is obtained, and the activity range of the cyclodextrin is limited to the polydimethylsiloxane chain and will not escape again.

[0060] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that the special coagulation bath in step 1 is composed of water and dimethylformamide, and the mass ratio thereof is (1:8) to (8:1). The other steps and parameters are the same as those in specific embodiment 1.

[0061] Specific implementation method 3: This implementation method is different from specific implementation method 2 in that the cyclodextrin in step 2 is β-cyclodextrin or γ-cyclodextrin, and the terminal group of the polydimethylsiloxane is an aminopropyl group with a molecular weight of 1000 to 5000 Da. Other steps and parameters are the same as those in specific implementation method 2.

[0062] Specific embodiment 4: This embodiment differs from specific embodiment 1 in that the saturated cyclodextrin solution in step 2 uses a solvent that matches the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the solvent is dimethylformamide; when the cyclodextrin is γ-cyclodextrin, the solvent is water. Other steps and parameters are the same as those in specific embodiment 1.

[0063] Specific implementation mode 5: This implementation mode is different from specific implementation mode 1 in that the parameters of ultrasound, shaking and standing in step 2 are adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the ultrasound power is 500-1500W, the time is 5-15min, the shaking rate is 50-100r / min, the time is 5-10d, and the standing time is 2d; when the cyclodextrin is γ-cyclodextrin, the ultrasound power is 200-600W, the time is 3-9min, the shaking rate is 50-100r / min, the time is 10-30h, and the standing time is 5-8h. The other steps and parameters are the same as those in specific implementation mode 1.

[0064] Specific embodiment 6: This embodiment is different from the specific embodiment 1 in that the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion is prepared in step 2: the solute concentration in the dispersion is 1 to 3 g / L, the solvent is dimethylformamide and distilled water, and the volume ratio of dimethylformamide to distilled water is (2:1) to (1:2); preparation of the dispersion: dissolving the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane in dimethylformamide, and then adding distilled water to ensure effective dispersion. The other steps and parameters are the same as those in the specific embodiment 1.

[0065] Specific embodiment 7: This embodiment is different from the specific embodiment 1 in that the mass concentration of the glycidyl methacrylate aqueous solution in step 3 is 1% to 3%, and the coating amount is 100 μl / cm 2 The other steps and parameters are the same as those in the first embodiment.

[0066] Specific embodiment 8: This embodiment is different from the specific embodiment 1 in that the ultraviolet irradiation in step 3: the ultraviolet intensity is 3 to 8 mW / cm 2 The irradiation time is 5 to 15 minutes. Other steps and parameters are the same as those in the first embodiment.

[0067] Specific embodiment 9: This embodiment is different from the specific embodiment 1 in that the amount of the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion in step 3 is 25 ml / cm 2 The other steps and parameters are the same as those in the first embodiment.

[0068] Specific embodiment 10: This embodiment is different from the specific embodiment 1 in that the fluorescein-4-isothiocyanate solution in step 3 has a concentration of 2.5 to 7.5 mg / mL and a dosage of 1.5 to 3.5 mL / cm 2 The other steps and parameters are the same as those in the first embodiment.

[0069] Specific embodiment 11: This embodiment differs from specific embodiment 1 in that the anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in step 3 is immersed in deionized water for 24 hours, and the water is replaced every 8 hours for standby use. The other steps and parameters are the same as those in specific embodiment 1.

[0070] The beneficial effects of the present invention are verified by the following examples:

[0071] Embodiment 1:

[0072] A method for preparing an anti-fouling membrane based on amphiphilic dynamic supramolecules is carried out according to the following steps:

[0073] 1. Preparation of high-flux polyethersulfone-based membrane:

[0074] Polyethersulfone, polyvinylpyrrolidone, Pluronic F127 and dimethylformamide were mixed in a mass ratio of 14:7:7:72 to form a casting solution, and then stirred at 70°C for 4 hours, and allowed to stand at 70°C for 4 hours to remove bubbles. After the casting solution was naturally cooled to 25°C, it was coated on a glass plate to form a 250 μm thick liquid film, and then immersed in a special coagulation bath for 5 minutes to obtain a base film, and then immersed in deionized water for ≥12 hours for standby use;

[0075] 2. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecular:

[0076] Adding polydimethylsiloxane to a saturated cyclodextrin solution, performing ultrasonication, shaking and standing in sequence, then precipitating the product, and then extracting and washing with cyclohexane, washing with distilled water and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, and then preparing a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion;

[0077] 3. Preparation of hydrophilic-low surface energy dynamic anti-pollution layer:

[0078] The base film prepared in step 1 is coated with a desalted aqueous solution of glycidyl methacrylate, then irradiated with ultraviolet light under nitrogen protection, and then washed with deionized water to obtain a membrane A;

[0079] At room temperature, the membrane A is immersed in the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, taken out and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, that is, an anti-fouling membrane based on amphoteric dynamic supramolecules, thereby completing the preparation method;

[0080] The product precipitation in step 2 is: removing 90% by weight of dimethylformamide by rotary evaporation, and then adding an equal weight of distilled water to induce the precipitation of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane;

[0081] The cyclodextrin / polydimethylsiloxane pseudopolyrotaxane obtained in step 2, wherein the cyclodextrin is β-cyclodextrin, the mass addition ratio of β-cyclodextrin to polydimethylsiloxane is 2.24:1, and the molar ratio of β-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.13:1;

[0082] The special coagulation bath in step 1 is composed of water and dimethylformamide in a mass ratio of 1:1;

[0083] The cyclodextrin in step 2 is β-cyclodextrin; the terminal group of the polydimethylsiloxane is aminopropyl, and its molecular weight is 3000Da;

[0084] The saturated cyclodextrin solution in step 2: wherein the cyclodextrin is β-cyclodextrin, and the solvent is dimethylformamide;

[0085] The ultrasound, shaking and standing in step 2 are as follows: ultrasound power 900 W, time 15 min, shaking rate 50 r / min, time 7 d, standing time 2 d.

[0086] In step 2, a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion is prepared: the solute concentration in the dispersion is 2 g / L, the solvent is dimethylformamide and distilled water, and the volume ratio of dimethylformamide to distilled water is 1:1; preparation of the dispersion: dissolving the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane in dimethylformamide, and then adding distilled water to ensure effective dispersion;

[0087] The mass concentration of the glycidyl methacrylate aqueous solution in step 3 is 2%, and the coating amount is 100 μl / cm 2 ;

[0088] UV irradiation in step 3: UV intensity is 5mW / cm 2 , irradiation time 10min;

[0089] The amount of the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion in step 3 is 25 ml / cm 2 ;

[0090] Fluorescein-4-isothiocyanate solution in step 3: concentration 5 mg / mL, dosage 2.5 mL / cm 2 ;

[0091] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in step 3 was immersed in deionized water for 24 hours, with the water replaced every 8 hours for standby use.

[0092] In step 1 of this embodiment, the high-flux polyethersulfone-based membrane is prepared by combining non-solvent-induced phase separation and surface segregation methods.

[0093] The base membrane obtained in step 1 of this embodiment has an ultrafiltration-grade pore size, and its porosity is 10% to 50% higher than that of conventional ultrafiltration membranes.

[0094] The hydrophilic-low surface energy amphiphilic dynamic supramolecule obtained in step 1 of this embodiment is a "line-through-ring" pseudo-polyrotaxane structure, in which cyclodextrin is a hydrophilic ring-shaped main body and polydimethylsiloxane is a low surface energy linear main body.

[0095] In step 2 of this embodiment, the hydrophilic-low surface energy amphiphilic dynamic supramolecule is prepared by a solvent-induced self-assembly method.

[0096] The purpose of ultraviolet irradiation in step three of this embodiment is to initiate free radical polymerization and graft glycidyl methacrylate onto the base film.

[0097] The purpose of the ionized water washing in step 3 of this embodiment is to remove the unreacted glycidyl methacrylate on the base film.

[0098] The immersion described in step three of this embodiment: during the immersion in the cyclodextrin / polydimethylsiloxane pseudo-polyrotaxane dispersion, the terminal amino group of the polydimethylsiloxane reacts with the epoxy group of glycidyl methacrylate, so that most of the pseudo-polyrotaxanes are double-end grafted to the polyglycidyl methacrylate to form a "clothes rod" structure, and are converted into polyrotaxanes due to the end blocking; during the immersion in the fluorescein-4-isothiocyanate solution, the residual amino group is blocked, so that almost all the pseudo-polyrotaxanes are converted into polyrotaxanes, and the activity range of the cyclodextrin is limited to the polydimethylsiloxane chain and will not escape again.

[0099] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as β-CD / PDMS@M-0.13, wherein CD is the abbreviation of cyclodextrin, PDMS is the abbreviation of polydimethylsiloxane, @ represents the load, M is the abbreviation of membrane, and -0.13 indicates that the molar ratio of cyclodextrin to polydimethylsiloxane is 0.13:1.

[0100] Embodiment 2:

[0101] In step 2 of this embodiment, the mass addition ratio of β-cyclodextrin and polydimethylsiloxane is 4.82:1, and the molar ratio of β-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27:1; the rest is the same as in embodiment 1.

[0102] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as β-CD / PDMS@M-0.27.

[0103] Embodiment 3:

[0104] In step 2 of this embodiment, the mass addition ratio of β-cyclodextrin and polydimethylsiloxane is 7.32:1, and the molar ratio of β-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.40:1; the rest is the same as in embodiment 1.

[0105] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as β-CD / PDMS@M-0.40.

[0106] Embodiment 4:

[0107] In step 2 of this embodiment, the mass addition ratio of β-cyclodextrin and polydimethylsiloxane is 10.10:1, and the molar ratio of β-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 00.53:1; the rest is the same as in embodiment 1.

[0108] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as β-CD / PDMS@M-0.53.

[0109] Embodiment 5:

[0110] In step 2 of this embodiment, the cyclodextrin is γ-cyclodextrin, and the solvent is water; the ultrasonic power is 400 W, the time is 5 min, the shaking rate is 50 r / min, the time is 24 h, and the standing time is 8 h; the γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane spontaneously forms a gel-like precipitate; the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is 2.45:1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.13:1; the rest is the same as in Example 1.

[0111] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as γ-CD / PDMS@M-0.13.

[0112] Embodiment 6:

[0113] In step 2 of this embodiment, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is 5.27:1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27:1; the rest is the same as in embodiment 5.

[0114] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as γ-CD / PDMS@M-0.27.

[0115] Embodiment 7:

[0116] In step 2 of this embodiment, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is 8.02:1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.40:1; the rest is the same as in embodiment 5.

[0117] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as γ-CD / PDMS@M-0.40.

[0118] Embodiment 8:

[0119] In step 2 of this embodiment, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is 10.81:1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 10.81:1; the rest is the same as in embodiment 5.

[0120] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as γ-CD / PDMS@M-0.53.

[0121] Embodiment 9:

[0122] In step 2 of this embodiment, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is 10.10:1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 13.79:1; the rest is the same as in embodiment 5.

[0123] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as γ-CD / PDMS@M-0.67.

[0124] Comparative Example:

[0125] In step 2 of this comparative example, cyclodextrin was not added; in step 3, polydimethylsiloxane was directly used for grafting reaction, and the solvent was cyclohexane; the rest was the same as in Example 1.

[0126] The amphoteric dynamic supramolecular anti-fouling membrane obtained in this example is denoted as PDMS@M.

[0127] result:

[0128] like Figure 1 As shown, the fluxes of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 1 to 4 at 5°C were 208.4, 286.6, 379.1, and 399.8 Lm, respectively. -2 h -1 The fluxes of γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53 and γ-CD / PDMS@M-0.67 obtained in Examples 5 to 9 at 5°C were 291.0, 340.1, 435.0, 438.4 and 445.7 Lm, respectively. -2 h -1 The flux of PDMS@M obtained in the comparative example at 5°C is 94.4Lm -2 h -1 .

[0129] like Figure 2 As shown, the fluxes of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 1 to 4 at 20°C were 289.1, 408.9, 481.2, and 474.1 Lm, respectively. -2 h -1 The fluxes of γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53 and γ-CD / PDMS@M-0.67 obtained in Examples 5 to 9 at 20°C were 405.2, 492.7, 546.2, 522.0 and 506.8 Lm, respectively. -2 h -1 The flux of PDMS@M obtained in the comparative example at 20°C is 126.91 Lm -2 h -1 .

[0130] like Figure 3 As shown, the fluxes of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 1 to 4 at 35°C were 397.6, 588.7, 618.8, and 554.0 Lm, respectively. -2 h -1The fluxes of γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53 and γ-CD / PDMS@M-0.67 obtained in Examples 5 to 9 at 35°C were 565.8, 735.5, 711.8, 623.6 and 612.6 Lm, respectively. -2 h -1 The flux of PDMS@M obtained in the comparative example at 35°C is 148.7Lm -2 h -1 .

[0131] like Figure 4 As shown, the fluxes of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 1 to 4 at 50°C were 479.0, 691.6, 693.7, and 646.5 Lm, respectively. -2 h -1 The fluxes of γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53 and γ-CD / PDMS@M-0.67 obtained in Examples 5 to 9 at 50°C were 725.8, 887.1, 860.7, 777.0 and 696.0 Lm, respectively. -2 h -1 The flux of PDMS@M obtained in the comparative example at 50°C is 181.2Lm -2 h -1 .

[0132] contrast Figure 1 to Figure 4 It can be seen that the dynamics of cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is beneficial to improving the membrane flux. Overall, the flux of γ-CD / PDMS@M is higher than that of β-CD / PDMS@M. When the mass ratio of cyclodextrin and polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27 and 0.4, it is most conducive to improving the flux.

[0133] like Figure 5As shown, the BSA retention rates of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, β-CD / PDMS@M-0.53 obtained in Examples 1 to 4, γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53, γ-CD / PDMS@M-0.67 obtained in Examples 5 to 9 and PDMS@M obtained in the comparative example are all slightly higher than 99%. The retention rate mainly depends on the pore size of the basement membrane and has no significant relationship with the modifier.

[0134] like Figure 6 As shown, the flux attenuation rates of β-CD / PDMS@M-0.13, β-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 1 to 4 were 32.9%, 28.8%, 25.2%, and 26.5%, respectively, and the flux recovery rates were 95.1%, 97.2%, 99.3%, and 97.7%, respectively. The flux recovery rates of γ-CD / PDMS@M-0.13, γ-CD / PDMS@M-0.27, β-CD / PDMS@M-0.40, and β-CD / PDMS@M-0.53 obtained in Examples 5 to 9 were 95.1%, 97.2%, 99.3%, and 97.7%, respectively. The flux attenuation rates of DMS@M-0.27, γ-CD / PDMS@M-0.40, γ-CD / PDMS@M-0.53 and γ-CD / PDMS@M-0.67 were 24.7%, 14.2%, 16.4%, 22.5% and 27.2%, respectively, and the flux recovery rates were 97.3%, 99.7%, 99.5%, 98.1% and 96.4%, respectively. The flux attenuation rate of PDMS@M obtained in the comparative example was 34.3%, and the flux recovery rate was 93.6%. The results show that the dynamics of cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is beneficial to improving the anti-fouling ability of the membrane. Overall, the anti-fouling ability of γ-CD / PDMS@M is higher than that of β-CD / PDMS@M. For β-CD / PDMS@M, the anti-fouling ability is best when the mass ratio of cyclodextrin to polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.4; for γ-CD / PDMS@M, the anti-fouling ability is best when the mass ratio of cyclodextrin to polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27.

[0135] like Figure 7 As shown, the β-CD / PDMS@M-0.40 and γ-CD / PDMS@M-0.27 obtained in Examples 3 and 6 are suitable for a pH range of 3 to 11, and have stronger anti-pollution capabilities under alkaline conditions (pH = 9, 11) or BSA isoelectric point conditions (pH = 5). The reason for the former is that the interaction between cyclodextrin and water molecules in an alkaline environment is stronger, and thus the dynamics are better, and the reason for the latter is that the BSA adsorption capacity is weakened under isoelectric point conditions.

[0136] like Figure 8 As shown, the β-CD / PDMS@M-0.40 and γ-CD / PDMS@M-0.27 obtained in Examples 3 and 6 still have excellent anti-pollution capabilities at low stirring rates. A stirring rate of more than 120 rpm can achieve the best anti-pollution effect for γ-CD / PDMS@M-0.27, and a stirring rate of more than 180 rpm can achieve the best anti-pollution effect for β-CD / PDMS@M-0.40.

[0137] like Fig. 9 As shown, the β-CD / PDMS@M-0.40 and γ-CD / PDMS@M-0.27 obtained in Examples 3 and 6 can maintain excellent anti-pollution effects in the range of 5°C to 50°C, and the anti-pollution effects remain almost constant in the range of 5°C to 35°C. The reason is that the temperature simultaneously increases the activity of cyclodextrin / polydimethylsiloxane polyrotaxane, the activity of water and the pollution tendency of pollutants, and the three reach a balance within a certain range.

[0138] like Fig.10 and 11 As shown, the β-CD / PDMS@M-0.40 and γ-CD / PDMS@M-0.27 obtained in Examples 3 and 6 have universal anti-pollution effects on a variety of pollutants, among which the flux attenuation of separating sodium alginate is the largest, followed by bovine serum albumin and emulsified hexadecane, and yeast and fulvic acid are the smallest.

[0139] In summary, the anti-fouling membrane based on the amphiphilic dynamic supramolecule prepared in this embodiment has good anti-fouling performance, adapts to different flow rates and temperature conditions, has high flux and low attenuation rate, and is suitable for a variety of water treatment processes. The comprehensive performance of the membrane can be precisely controlled by regulating the membrane preparation parameters. For example, different types of cyclodextrin have different dynamic characteristics. Within the scope of this embodiment, the dynamics of γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane are better than those of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, so γ-CD / PDMS@M has a higher flux and better anti-pollution performance overall; by regulating the mass addition ratio of cyclodextrin and polydimethylsiloxane, the comprehensive performance of the membrane can be precisely optimized. For β-CD / PDMS@M, when the mass ratio of cyclodextrin and polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.4, it has the best comprehensive performance; for γ-CD / PDMS@M, when the mass ratio of cyclodextrin and polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27, it has the best comprehensive performance.

[0140] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the purpose of the present invention, all of which are within the protection of the present invention.

Claims

1. A method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules, characterized in that It proceeds as follows:

1. Preparation of high-flux polyethersulfone-based membrane: Polyethersulfone, polyvinylpyrrolidone, Pluronic F127 and dimethylformamide were mixed in a mass ratio of 14:7:7:72 to form a casting solution, and then stirred at 70°C for 4 hours, and allowed to stand at 70°C for 4 hours to remove bubbles. After the casting solution was naturally cooled to 25°C, it was coated on a glass plate to form a 250 μm thick liquid film, and then immersed in a special coagulation bath for 5 minutes to obtain a base film, and then immersed in deionized water for ≥12 hours for standby use; 2. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecular: Adding polydimethylsiloxane to a saturated cyclodextrin solution, performing ultrasonication, shaking and standing in sequence, then precipitating the product, and then extracting and washing with cyclohexane, washing with distilled water and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, and then preparing a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion; 3. Preparation of hydrophilic-low surface energy dynamic anti-pollution layer: The base film prepared in step 1 is coated with a desalted aqueous solution of glycidyl methacrylate, then irradiated with ultraviolet light under nitrogen protection, and then washed with deionized water to obtain a membrane A; At room temperature, the membrane A is immersed in the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, taken out and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, that is, an anti-fouling membrane based on amphoteric dynamic supramolecules, thereby completing the preparation method; The product in step 2 is precipitated: the precipitation method is adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, 60% to 90% by weight of dimethylformamide is removed by rotary evaporation, and then an equal amount of distilled water is added to induce the precipitation of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane; when the cyclodextrin is γ-cyclodextrin, γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane will spontaneously form a gel-like precipitate; The cyclodextrin / polydimethylsiloxane pseudopolyrotaxane obtained in step 2, wherein the molar ratio of cyclodextrin to polydimethylsiloxane depends on the type of cyclodextrin and the mass addition ratio of cyclodextrin to polydimethylsiloxane; When the cyclodextrin is β-cyclodextrin, the mass addition ratio of β-cyclodextrin to polydimethylsiloxane is (2.24-10.10):1, and the molar ratio of β-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.53):1; When the cyclodextrin is γ-cyclodextrin, the mass addition ratio of γ-cyclodextrin and polydimethylsiloxane is (2.45-13.78):1, and the molar ratio of γ-cyclodextrin and polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is (0.13-0.67):

1.

2. The method for preparing an anti-pollution membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The special coagulation bath described in step 1 is composed of water and dimethylformamide, and the mass ratio thereof is (1:8) to (8:1).

3. The method for preparing an anti-pollution membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The cyclodextrin in step 2 is β-cyclodextrin or γ-cyclodextrin; the terminal group of the polydimethylsiloxane is aminopropyl, and its molecular weight is 1000-5000Da.

4. The method for preparing an anti-pollution membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The saturated cyclodextrin solution in step 2, wherein the solvent used is compatible with the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the solvent is dimethylformamide; when the cyclodextrin is γ-cyclodextrin, the solvent is water.

5. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The ultrasound, shaking and standing in step 2: the parameters are adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the ultrasonic power is 500-1500W, the time is 5-15min, the shaking rate is 50-100r / min, the time is 5-10d, and the standing time is 2d; when the cyclodextrin is γ-cyclodextrin, the ultrasonic power is 200-600W, the time is 3-9min, the shaking rate is 50-100r / min, the time is 10-30h, and the standing time is 5-8h.

6. The method for preparing an anti-pollution membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that In step 2, a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion is prepared: the solute concentration in the dispersion is 1 to 3 g / L, the solvent is dimethylformamide and distilled water, and the volume ratio of dimethylformamide to distilled water is (2:1) to (1:2); preparation of the dispersion: dissolve the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane in dimethylformamide, and then add distilled water to ensure effective dispersion.

7. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The mass concentration of the glycidyl methacrylate aqueous solution in step 3 is 1% to 3%, and the coating amount is 100 μl / cm 2 .

8. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that Ultraviolet irradiation in step 3: ultraviolet intensity is 3-8mW / cm 2 The irradiation time is 5 to 15 minutes.

9. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The amount of the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion in step 3 is 25 ml / cm 2 ; The fluorescein-4-isothiocyanate solution in step 3: the concentration is 2.5-7.5 mg / mL, the dosage is 1.5-3.5 mL / cm 2 .

10. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecules according to claim 1, characterized in that The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in step 3 was immersed in deionized water for 24 hours, with the water replaced every 8 hours for standby use.

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