Preparation method of anti-fouling film based on zwitterionic dynamic supramolecule

Abstract

The application discloses a preparation method of an anti-pollution membrane based on amphoteric dynamic supramolecules, and belongs to the technical field of membrane preparation for water treatment. The method comprises the following steps: preparing a high-flux base membrane through a non-solvent induced phase separation method; preparing an amphoteric supramolecule with a "thread penetrating ring" quasi-polyrotaxane structure through a solvent induced self-assembly method; and grafting the amphoteric dynamic supramolecule to the surface of the base membrane based on a free radical polymerization reaction to form an anti-pollution layer. Supramolecular structures formed by cyclodextrin and polydimethylsiloxane are combined with a synergistic anti-pollution mechanism of hydrophilicity and a low-surface-energy micro area to improve the anti-pollution performance and water flux of the membrane. The dynamic supramolecular structure has good anti-pollution performance, is suitable for different flow rates and temperature conditions, has a high flux and a low 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 significantly improved, the anti-pollution capacity is enhanced, and the performance can be easily restored through simple cleaning; and the membrane has good adaptability in a wide temperature and pH range.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment membrane preparation, and particularly relates to a preparation method of an anti-fouling membrane based on amphoteric dynamic supramolecules. BACKGROUND

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

[0003] In order to further improve the anti-fouling performance of the membrane, heterogeneous membranes have gradually attracted attention. This kind of membrane combines the fouling resistance and fouling release mechanisms by constructing hydrophilic and low surface energy heterogeneous microzones on the membrane surface. The hydrophilic microzone can prevent the initial adhesion of pollutants, while the low surface energy microzone can promote the release of pollutants under external disturbance conditions by reducing the adhesion of pollutants to the membrane surface. This synergistic anti-fouling mechanism can significantly improve the anti-fouling ability of the membrane in actual operation, especially in the case where some pollutants have already adhered, the low surface energy microzone can effectively reduce the residue of the pollutants. However, the application of heterogeneous membranes in water treatment also faces some challenges, including that the mechanism usually relies on strong tangential flow, and the low surface energy hydrophobic microzone may increase the water flow resistance of the membrane, affecting the water flux of the membrane; therefore, improving the basic flux of the heterogeneous anti-fouling membrane and solving the dependence of the heterogeneous membrane on the tangential flow rate are the research focuses in the field, in order to prepare high-quality water treatment membranes with low cost, high flux and anti-fouling properties, and solve the problems of easy fouling and performance degradation of traditional membranes in the water treatment process. SUMMARY

[0004] The direct purpose of the present application is to improve the basic flux of the heterogeneous anti-fouling membrane and solve the problem of dependence of the heterogeneous membrane on the tangential flow rate, and the fundamental purpose is to prepare high-quality water treatment membranes with low cost, high flux and anti-fouling properties, and therefore a preparation method of an anti-fouling membrane based on amphoteric dynamic supramolecules is provided.

[0005] A preparation method of an anti-fouling membrane based on amphoteric dynamic supramolecules, which is carried out according to the following steps:

[0006] I. Preparation of high-flux polyether sulfone-based membrane:

[0007] Mix polyether sulfone, polyvinylpyrrolidone, pluronic F127 and dimethylformamide in a mass ratio of 14:7:7:72 to form a casting solution, then stir at 70℃ for 4h, remove bubbles at 70℃ for 4h, and then naturally cool the casting solution to 25℃, coat on a glass plate to form a 250μm thick liquid film, then immerse in a special coagulation bath for 5min to obtain a base film, and then immerse in deionized water for ≥12h for standby;

[0008] II. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecule:

[0009] Add polydimethylsiloxane to a saturated cyclodextrin solution, and then sequentially perform ultrasonic treatment, shaking and standing, then precipitate the product, and then perform cyclohexane extraction washing, distilled water washing and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, i.e. cyclodextrin / polydimethylsiloxane quasi-polyrotaxane, and then configure a cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion solution;

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

[0011] Coat a desalted glycidyl methacrylate aqueous solution on the base film prepared in step one, then irradiate with ultraviolet light under nitrogen protection, and then wash with deionized water to obtain film A;

[0012] Immerse film A in the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion solution configured in step two at room temperature for 12h, then immerse in a fluorescein-4-isothiocyanate solution for 3h after taking out, to obtain a hydrophilic-low surface energy dynamic anti-pollution layer, i.e. an anti-pollution film based on an amphiphilic dynamic supramolecule, and complete the preparation method;

[0013] In step two, the product precipitation: 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 mass of distilled water is added to induce precipitation of β-cyclodextrin / polydimethylsiloxane quasi-polyrotaxane; when the cyclodextrin is γ-cyclodextrin, γ-cyclodextrin / polydimethylsiloxane quasi-polyrotaxane spontaneously forms a gel-like precipitate;

[0014] The cyclodextrin / polydimethylsiloxane quasi-polyrotaxane obtained in step two, wherein the molar ratio of cyclodextrin and polydimethylsiloxane depends on the type of cyclodextrin and the mass ratio of cyclodextrin and polydimethylsiloxane;

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

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

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

[0018] Further, the cyclodextrin in step two is β-cyclodextrin or γ-cyclodextrin; and the end group of the polydimethylsiloxane is aminopropyl, and the molecular weight is 1000-5000 Da.

[0019] Further, the saturated cyclodextrin solution in step two is adapted to the type of cyclodextrin and solvent; when the cyclodextrin is β-cyclodextrin, the solvent is dimethylformamide; and when the cyclodextrin is γ-cyclodextrin, the solvent is water.

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

[0021] Further, the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion liquid in step two has a solute concentration of 1-3 g / L, and the solvent is dimethylformamide and distilled water, and the volume ratio of dimethylformamide to distilled water is (2:1)-(1:2); and the preparation of the dispersion liquid: the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane is dissolved in dimethylformamide, and then distilled water is added to ensure effective dispersion.

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

[0023] Further, the amount of the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion liquid in step three is 25 ml / cm 2 .

[0024] Further, the ultraviolet irradiation in step three: the ultraviolet intensity is 3-8 mW / cm 2 , and the irradiation time is 5-15 min.

[0025] Further, the fluorescein-4-isothiocyanate solution in step three: concentration of 2.5-7.5 mg / mL, dosage of 1.5-3.5 mL / cm 2 .

[0026] Further, the obtained anti-fouling film based on the amphoteric dynamic supramolecule in step three is soaked in deionized water for 24 h, and the water is replaced every 8 h for standby.

[0027] In the present application, the anti-fouling film based on the amphoteric dynamic supramolecule is an anti-fouling film based on the dynamic nature of heterogeneous supramolecules. For the first time, the heterogeneous film hydrophilic-low surface energy synergistic anti-fouling mechanism is combined with the dynamic characteristics of supramolecules. Compared with conventional heterogeneous membranes, the base flux is higher, and the dependence on the tangential water flow velocity is small, and the excellent anti-fouling ability can be maintained in a weak disturbance environment; compared with existing supramolecular membranes, the interaction between the amphoteric supramolecular host and guest is lower, and the activity is stronger, supplemented by the synergistic anti-fouling mechanism, the anti-fouling ability is improved by leaps and bounds.

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

[0029] (1) The raw materials used in the present application are easy to obtain and cheap, and can be prepared at room temperature without atmosphere protection. The anti-fouling film based on the amphoteric dynamic supramolecule can be prepared using a conventional membrane production line for phase inversion preparation-surface coating modification.

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

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

[0032] (4) The amphoteric dynamic supramolecular anti-fouling film performs well in a pH range of 3-11, and the alkaline condition can strengthen the interaction between cyclodextrin and water molecules, which is beneficial to further improve the anti-fouling ability.

[0033] (5) The amphoteric dynamic supramolecular anti-fouling film has high flux, high adaptability and low maintenance, and is suitable for various water treatment processes, including drinking water deep treatment, multi-stage sewage treatment and reuse, etc.

[0034] The present application is suitable for the preparation of an anti-fouling film based on the amphoteric dynamic supramolecule. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figures 1 to 4are flux data graphs of examples 1-9 and comparative examples at temperature 5℃, 20℃, 35℃, 50℃ and pressure 1.0 bar, respectively;

[0036] Figure 5 are bovine serum albumin (BSA) rejection data graphs of examples 1-9 and comparative examples; wherein BSA concentration in feed is 1 g / L, neutral environment, temperature 20℃, stirring rate 60 rpm.

[0037] Figure 6 are anti-fouling capacity data graphs of examples 1-9 and comparative examples with BSA as simulated pollutant; wherein base water flux test time is 15 min, sewage treatment flux test time is 30 min, cleaning time is 15 min, water flux test time after cleaning is 15 min, neutral environment, temperature 20℃, running stirring rate 60 rpm, cleaning stirring rate 480 rpm; flux decay rate (FDR) is (base water flux-sewage treatment flux) / base water flux, flux recovery rate (FRR) is water flux after cleaning / base water flux;

[0038] Figure 7 、 8 , 9 are anti-fouling capacity data graphs of examples 3 and 6 with BSA as simulated pollutant in different pH environment, different stirring rate environment and different temperature environment, respectively;

[0039] Figure 10 and 11 are anti-fouling capacity data graphs of examples 3 and 6 separating different simulated pollutants, respectively; wherein simulated pollutants include BSA, emulsified hexadecane, sodium alginate (SA), yeast, humic acid (HA), and the concentration of each is 1 g / L, and the emulsified hexadecane additionally contains 0.1 g / L of sodium dodecyl sulfate; base water flux test time is 15 min, sewage treatment time is 30 min, cleaning time is 15 min, water flux test time after cleaning is 15 min, repeated 5 times, base water flux in the second cycle is water flux after cleaning in the first cycle, neutral environment, temperature 20℃, running stirring rate 60 rpm, cleaning stirring rate 480 rpm. DETAILED DESCRIPTION

[0040] The technical solution of the present application is not limited to the following specific embodiments, and also includes any combination of the specific embodiments.

[0041] Specific embodiment one: the present embodiment is a preparation method of an anti-fouling membrane based on amphoteric dynamic supramolecule, which is carried out according to the following steps:

[0042] I. Preparation of high-flux polyether sulfone-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, which was 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, which was then immersed in a special coagulation bath for 5 minutes to obtain a base film, which was then immersed in deionized water for ≥12 hours for standby use.

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

[0045] Polydimethylsiloxane is added to a saturated cyclodextrin solution, and the solution is subjected to ultrasonication, shaking, and standing in sequence. The product is then precipitated and then subjected to cyclohexane extraction, washing with distilled water, and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, a cyclodextrin / polydimethylsiloxane pseudopolyrotaxane. A cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion is then prepared.

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

[0047] The base film prepared in step 1 is coated with a desalted glycidyl methacrylate aqueous solution, which is 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 was immersed in the cyclodextrin / polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, i.e., an anti-fouling membrane based on amphiphilic dynamic supramolecules, thereby completing the preparation method;

[0049] The product is precipitated in step 2: 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 weight of distilled water is added to induce precipitation of the β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane; when the cyclodextrin is γ-cyclodextrin, the 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 ratio of γ-cyclodextrin to polydimethylsiloxane is (2.45-13.78):1, and the molar ratio of γ-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin / polydimethylsiloxane quasi-polyrotaxane is (0.13-0.67):1.

[0053] In step one of the embodiment, the high-flux polyether sulfone base film is prepared by combining the non-solvent induced phase separation and surface segregation method.

[0054] The base film obtained in step one of the embodiment has an ultrafiltration level pore size, and the porosity is 10%-50% higher than that of a conventional ultrafiltration membrane.

[0055] The hydrophilic-low surface energy amphiphilic dynamic supramolecule obtained in step one of the embodiment is a "thread-in-ring" quasi-polyrotaxane structure, in which the cyclodextrin is a hydrophilic ring-shaped host and the polydimethylsiloxane is a low surface energy linear host.

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

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

[0058] In step three of the embodiment, the purpose of ion water washing is to remove unreacted glycidyl methacrylate on the base film.

[0059] In step three of the embodiment, the soaking: during soaking in the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion, addition reaction occurs between the polydimethylsiloxane terminal amino group and the epoxy group of glycidyl methacrylate, so that most of the quasi-polyrotaxanes are grafted at both ends of the polyglycidyl methacrylate to form a "clothesline" structure, and are converted into polyrotaxanes due to end-capping; during soaking in the fluorescein-4-isothiocyanate solution, the residual amino groups are capped, so that almost all the quasi-polyrotaxanes are converted into polyrotaxanes, and cyclodextrin / polydimethylsiloxane polyrotaxanes are obtained, and the movement range of cyclodextrin is limited on the polydimethylsiloxane chain and cannot be released.

[0060] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the special coagulation bath in step one is composed of water and dimethylformamide, and the mass ratio is (1:8)-(8:1). The other steps and parameters are the same as those in specific embodiment one.

[0061] Specific embodiment three: the difference between this embodiment and specific embodiment two is that the cyclodextrin in step two is β-cyclodextrin or γ-cyclodextrin; and the polydimethylsiloxane end group is an aminopropyl group with a molecular weight of 1000-5000 Da. The other steps and parameters are the same as those in specific embodiment two.

[0062] Specific embodiment four: the difference between this embodiment and the first embodiment is that the saturated cyclodextrin solution in step two is adapted to the type of cyclodextrin and solvent used; when the cyclodextrin is β-cyclodextrin, the solvent is dimethylformamide; when the cyclodextrin is γ-cyclodextrin, the solvent is water. The other steps and parameters are the same as the first embodiment.

[0063] Specific embodiment five: the difference between this embodiment and the first embodiment is that the ultrasonic, shaking and standing in step two are adapted to the type of cyclodextrin; when the cyclodextrin is β-cyclodextrin, the ultrasonic power is 500-1500 W, the time is 5-15 min, the shaking rate is 50-100 r / min, the time is 5-10 d, and the standing time is 2 d; when the cyclodextrin is γ-cyclodextrin, the ultrasonic power is 200-600 W, the time is 3-9 min, the shaking rate is 50-100 r / min, the time is 10-30 h, and the standing time is 5-8 h. The other steps and parameters are the same as the first embodiment.

[0064] Specific embodiment six: the difference between this embodiment and the first embodiment is that the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion solution in step two is prepared by dissolving the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane in dimethylformamide and then adding distilled water to ensure effective dispersion. The solute concentration in the dispersion solution is 1-3 g / L, and the solvent is dimethylformamide and distilled water, with a volume ratio of (2:1) to (1:2). The other steps and parameters are the same as the first embodiment.

[0065] Specific embodiment seven: the difference between this embodiment and the first embodiment is that the mass concentration of the glycidyl methacrylate aqueous solution in step three is 1%-3%, and the coating amount is 100 μl / cm 2 . The other steps and parameters are the same as the first embodiment.

[0066] Specific embodiment eight: the difference between this embodiment and the first embodiment is that the ultraviolet irradiation in step three is at an intensity of 3-8 mW / cm 2 for 5-15 min. The other steps and parameters are the same as the first embodiment.

[0067] Specific embodiment nine: the difference between this embodiment and the first embodiment is that the amount of the cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion solution used in step three is 25 ml / cm 2 . The other steps and parameters are the same as the first embodiment.

[0068] Specific embodiment ten: different from specific embodiment one, the fluorescein-4-isothiocyanate solution in step three: concentration of 2.5-7.5 mg / mL, dosage of 1.5-3.5 mL / cm 2 . Other steps and parameters are the same as specific embodiment one.

[0069] Specific embodiment eleven: different from specific embodiment one, the anti-pollution film based on amphoteric dynamic supramolecule obtained in step three is soaked in deionized water for 24 h, and the water is replaced every 8 h, ready for use. Other steps and parameters are the same as specific embodiment one.

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

[0071] Example 1:

[0072] A preparation method of an anti-pollution film based on amphoteric dynamic supramolecule, which is carried out according to the following steps:

[0073] I. Preparation of high-flux polyether sulfone-based film:

[0074] Polyether sulfone, polyvinylpyrrolidone, pluronic F127 and dimethylformamide are mixed in a mass ratio of 14:7:7:72 to form a casting solution, then stirred at 70°C for 4h, deaerated at 70°C for 4h, and then naturally cooled to 25°C. After the casting solution is coated on a glass plate to form a liquid film with a thickness of 250μm, it is immersed in a special coagulation bath for 5min to obtain a base film, and then soaked in deionized water for ≥12h, ready for use;

[0075] II. Preparation of hydrophilic-low surface energy amphoteric dynamic supramolecule:

[0076] Polydimethylsiloxane is added to a saturated cyclodextrin solution, and then ultrasonic, shaking and standing are carried out in sequence. Then the product is precipitated, and then washed with cyclohexane extraction, distilled water and vacuum drying to obtain a hydrophilic-low surface energy amphoteric dynamic supramolecule, i.e. cyclodextrin / polydimethylsiloxane quasi-polyrotaxane, and then a cyclodextrin / polydimethylsiloxane quasi-polyrotaxane dispersion solution is prepared.

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

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

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

[0080] wherein the product is precipitated in step 2 by removing 90% by weight of dimethylformamide by rotary evaporation, and then adding an equal weight of distilled water to induce 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 ultrasonication, shaking and standing in step 2 are as follows: ultrasonic power 900 W, time 15 min, shaking rate 50 r / min, time 7 d, and 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, and the solvent is dimethylformamide and distilled water, wherein 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] Ultraviolet 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, and set aside.

[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 a conventional ultrafiltration membrane.

[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 unreacted glycidyl methacrylate on the base film.

[0098] The immersion described in step 3 of this embodiment: During the immersion in the cyclodextrin / polydimethylsiloxane pseudo-polyrotaxane dispersion, the terminal amino groups of the polydimethylsiloxane react with the epoxy groups of the glycidyl methacrylate, resulting in the majority of the pseudo-polyrotaxane being grafted onto the polyglycidyl methacrylate at both ends, forming a "clothesline" structure, and being converted into a polyrotaxane due to the end capping; during the immersion in the fluorescein-4-isothiocyanate solution, the residual amino groups are capped, resulting in the conversion of almost all the pseudo-polyrotaxanes into polyrotaxanes, and the activity range of the cyclodextrin is confined to the polydimethylsiloxane chain, preventing it from escaping.

[0099] The anti-fouling membrane based on the amphiphilic dynamic supramolecule obtained in this example is recorded as β-CD / PDMS@M-0.13, where 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] Example 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; other aspects are 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] Example 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; other aspects are 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] Example 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; other aspects are 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] Example 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 to polydimethylsiloxane is 2.45:1, and the molar ratio of γ-cyclodextrin to polydimethylsiloxane in the resulting cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.13:1; all other aspects are 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] Example 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; other aspects are the same as in Example 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] Example 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 Example 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] Example 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 Example 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] Example 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 Example 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 94.4 Lm -2 h -1 .

[0129] like Figure 2 As shown in Figure 2, 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 in Figure 2, 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 Figures 1 to 4 It can be seen that the dynamics of cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is beneficial to improving 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 to polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27 and 0.4, it is most conducive to improving 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, and 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, and 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 attenuation 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 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 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%. Analysis shows 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 the 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 the 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-fouling ability 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 is stronger in an alkaline environment, resulting in better dynamics, 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 exhibited excellent anti-fouling capabilities even at low stirring rates. Stirring rates above 120 rpm enabled γ-CD / PDMS@M-0.27 to achieve optimal anti-fouling performance, while stirring rates above 180 rpm enabled β-CD / PDMS@M-0.40 to achieve optimal anti-fouling performance.

[0137] like Figure 9 As shown, the β-CD / PDMS@M-0.40 and γ-CD / PDMS@M-0.27 obtained in Examples 3 and 6 maintain excellent anti-fouling effects within the 5°C to 50°C range, and the anti-fouling effects remain almost constant within the 5°C to 35°C range. This is because temperature simultaneously increases the mobility of the cyclodextrin / polydimethylsiloxane polyrotaxane, the activity of water, and the contamination tendency of the pollutants, achieving equilibrium among the three within a certain range.

[0138] like Figure 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 for separating sodium alginate is the largest, followed by bovine serum albumin and emulsified hexadecane, and the smallest for yeast and fulvic acid.

[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 dynamic properties of γ-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane are better than those of β-cyclodextrin / polydimethylsiloxane pseudopolyrotaxane, so that γ-CD / PDMS@M has a higher flux and better anti-fouling 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, the optimal comprehensive performance is achieved when the mass ratio of cyclodextrin to polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.4; for γ-CD / PDMS@M, the optimal comprehensive performance is achieved when the mass ratio of cyclodextrin to polydimethylsiloxane in cyclodextrin / polydimethylsiloxane pseudopolyrotaxane is 0.27.

[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. The above-mentioned specific embodiments are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many variations without departing from the purpose of the present invention, and these are all protected by 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, which was 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, which was then immersed in a coagulation bath for 5 minutes to obtain a base film, which was then immersed in deionized water for 12 hours or more for later use.

2. Preparation of hydrophilic-low surface energy amphiphilic dynamic supramolecular molecules: Polydimethylsiloxane is added to a saturated cyclodextrin solution, and the solution is subjected to ultrasonication, shaking, and standing in sequence. The product is then precipitated and then subjected to cyclohexane extraction, washing, distilled water washing, and vacuum drying to obtain a hydrophilic-low surface energy amphiphilic dynamic supramolecule, namely, cyclodextrin-polydimethylsiloxane pseudopolyrotaxane. A cyclodextrin-polydimethylsiloxane pseudopolyrotaxane dispersion is then prepared.

3. Preparation of hydrophilic-low surface energy dynamic anti-fouling layer: The base film prepared in step 1 is coated with a desalted glycidyl methacrylate aqueous solution, which is 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 was immersed in the cyclodextrin-polydimethylsiloxane pseudopolyrotaxane dispersion prepared in step 2 for 12 hours, and then immersed in a fluorescein-4-isothiocyanate solution for 3 hours to obtain a hydrophilic-low surface energy dynamic anti-fouling layer, i.e., an anti-fouling membrane based on amphiphilic dynamic supramolecules, thereby completing the preparation method; The product is precipitated in step 2: 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 weight of distilled water is added to induce the precipitation of β-cyclodextrin-polydimethylsiloxane pseudopolyrotaxane; when the cyclodextrin is γ-cyclodextrin, the 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 to polydimethylsiloxane is (2.45-13.78):1, and the molar ratio of γ-cyclodextrin to polydimethylsiloxane in the obtained cyclodextrin-polydimethylsiloxane pseudopolyrotaxane is (0.13-0.67):1; The coagulation bath in step 1 is composed of water and dimethylformamide in a mass ratio of (1:8) to (8:1).

2. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecule 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 1000~5000 Da.

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

4. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecule according to claim 1, characterized in that The ultrasonic, shaking and standing parameters in step 2 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.

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

6. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecule 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 / cm².

7. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecule according to claim 1, characterized in that Ultraviolet irradiation in step 3: the ultraviolet intensity is 3 to 8 mW / cm², and the irradiation time is 5 to 15 minutes.

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

9. The method for preparing an anti-fouling membrane based on amphoteric dynamic supramolecule 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, and set aside.

Images