阅读说明：本技术 一种亲水性耐氯聚砜膜制备与应用 (Preparation and application of hydrophilic chlorine-resistant polysulfone membrane ) 是由 郭红霞 张梦蕾 秦振平 贾萌萌 崔素萍 于 2021-01-11 设计创作，主要内容包括：一种亲水性耐氯聚砜膜制备与应用,属于膜分离技术领域。采用硅烷偶联剂辅助环糊精界面聚合方法对聚砜膜进行改性,得到亲水性耐氯聚砜膜。本发明制备的硅烷偶联剂辅助环糊精界面聚合改性聚砜复合膜具有较好的亲水性和耐氯性能。(Preparation and application of a hydrophilic chlorine-resistant polysulfone membrane, belonging to the technical field of membrane separation. And modifying the polysulfone membrane by adopting a silane coupling agent assisted cyclodextrin interfacial polymerization method to obtain the hydrophilic chlorine-resistant polysulfone membrane. The polysulfone composite membrane prepared by the invention has better hydrophilicity and chlorine resistance by the silane coupling agent assisted cyclodextrin interfacial polymerization modification.)

1. A preparation method of a hydrophilic chlorine-resistant polysulfone membrane is characterized by comprising the following steps:

(1) preparation of modified liquid

Under the condition of stirring, dissolving Cyclodextrin (CD) and a silane coupling agent in water according to the mass ratio of 40: 1-5: 1 to ensure that the concentration of the cyclodextrin is 0.5-2.0 wt%, and completely dissolving to obtain a cyclodextrin water solution containing the silane coupling agent as an aqueous phase solution of interfacial polymerization. In addition, adding an organic phase monomer containing acyl chloride groups into n-hexane under the stirring condition, and fully dissolving to obtain 0.15-1.0 wt% of an n-hexane solution of an organic phase containing acyl chloride groups, wherein the n-hexane solution is used as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Immersing the fully cleaned and pretreated polysulfone ultrafiltration membrane into the water phase solution prepared in the step (1) for 5-50 min by adopting an immersion method, taking out the polysulfone ultrafiltration membrane, and then putting the polysulfone ultrafiltration membrane into the oil phase solution prepared in the step (1), so that the cyclodextrin containing the silane coupling agent and the organic phase monomer containing acyl chloride groups in the oil phase are subjected to interfacial polymerization on the surface of the polysulfone membrane;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization is finished, placing the modified polysulfone composite membrane obtained in the step (2) in an oven, carrying out heat treatment at the temperature of 40-110 ℃ for 15-60 min, taking out, placing in an aqueous solution with the pH value of 8-13 for 1-3 h, taking out, and cleaning with deionized water to obtain the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

2. The method of claim 1, wherein the polysulfone membrane is a polysulfone ultrafiltration membrane with a molecular weight cut-off of 10-100 kDa.

3. The method for preparing a hydrophilic polysulfone membrane resistant to chlorine according to claim 1, wherein the cyclodextrin is an outer hydrophilic and inner hydrophobic nanocavity structure containing a plurality of hydroxyl groups, and mainly comprises α -cyclodextrin (α -CD), β -cyclodextrin (β -CD), γ -cyclodextrin (γ -CD), amino-cyclodextrin (H-CD)₂N-CD) and hydroxypropyl- β -cyclodextrin (HP- β -CD), preferably β -CD and HP- β -CD.

4. The method for preparing a hydrophilic chlorine-resistant polysulfone membrane according to claim 1, wherein the silane coupling agent includes but is not limited to γ -aminopropyltriethoxysilane (KH-550), γ - (2, 3-epoxypropoxy) propyltriethoxysilane (KH-560), γ - (methacryloyloxy) propyltriethoxysilane (KH-570) and γ -mercaptopropyltriethoxysilane (KH-580), preferably KH-550, KH-560;

5. the method for preparing a hydrophilic chloride-resistant polysulfone membrane according to claim 1, wherein the organic phase monomer containing acid chloride group mainly comprises trimesoyl chloride (TMC), isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), preferably TMC.

6. A hydrophilic chloride-resistant polysulfone membrane prepared according to the method of any of claims 1-5.

7. Use of the hydrophilic chlorine-resistant polysulfone membrane prepared according to any of claims 1-5 as a filtration membrane for the filtration of an aqueous evans blue solution, with a sodium hypochlorite rinse for recovery.

Technical Field

The invention relates to preparation and application of a high-performance polysulfone membrane, in particular to preparation and application technology of a hydrophilic chlorine-resistant polysulfone membrane, and belongs to the technical field of membrane separation.

Background

Polysulfone membranes have the characteristics of strong acid and alkali resistance, high thermal stability, stable mechanical properties and the like, and are one of the most common polymer separation membranes in the industry at present. However, since the polysulfone membrane surface is hydrophobic, it is easily contaminated by organic solutes, resulting in a decrease in separation performance. Researchers adopt various methods toThe modification mainly comprises chemical modification, interfacial polymerization, surface impregnation, layer-by-layer self-assembly, physical blending and the like. In patent CN111437740A, sodium lignosulfonate containing hydroxyl, carboxyl and sulfonic acid groups is used as a water phase, trimesoyl chloride (TMC) is used as an oil phase, interfacial polymerization is carried out on the surface of a polysulfone base membrane to prepare a polysulfone nanofiltration membrane for separating a sunset yellow dye aqueous solution, and the result shows that the permeation flux of the nanofiltration membrane is 14.03L/m²H.bar, the retention rate of the sunset yellow dye reaches 99.02 percent. The patent CN111249920A fixes a synthesized metal organic framework nanosheet (Zn-TCPP) on a polysulfone base membrane through a filter pressing method, then the membrane containing the Zn-TCPP nanosheet on the surface is respectively impregnated with m-phenylenediamine (MPD) water phase and TMC oil phase for interfacial polymerization to obtain the polysulfone reverse osmosis membrane containing a polyamide thin layer, the polysulfone reverse osmosis membrane is used for separating 2000ppm sodium chloride (NaCl), the rejection rate is about 97%, and the flux can reach 5L/m at most²H.bar; zhang Yufeng uses hyperbranched Polyethyleneimine (PEI) as water phase, TMC as oil phase to perform interfacial polymerization on the surface of polysulfone membrane to prepare polyamide nanofiltration membrane for 0.1% magnesium sulfate (MgSO)₄) The result shows that the nanofiltration membrane is MgSO 2₄The retention rate of the magnetic flux reaches 95 percent, and the flux is 55L/m²H, (university of Tianjin, school, 2019, 38(1): 1-6). The surface hydrophilicity of the polyamide modified composite membrane is improved, but active chlorine is inevitably used to inhibit the propagation of microorganisms in water during the actual use process. Thus, the generated chloride ions are liable to react with amide groups on the membrane surface, and damage the membrane surface, which results in destruction of the separation layer and deterioration of the separation performance. In order to improve the chlorine resistance of the polyamide membrane, patent CN109364758A discloses a method for depositing a silane coupling agent containing amino or acyloxy groups on the surface of the polyamide membrane, and reacting-Si-OH with N-H in amide bonds using an alkali catalyst to reduce the attack of active chlorine on the amide sites, and at the same time, fixing the silane coupling agent coating on the membrane surface in a chemical bond manner.

Cyclodextrin is a cyclic oligosaccharide formed by connecting glucose units through alpha-1, 4 glycosidic bonds, and the outer wall of a cyclic cavity structure of the cyclodextrin is connected with a plurality of hydroxyl groups. In order to improve the hydrophilicity of a polyamide membrane prepared by interfacial polymerization and improve the anti-pollution performance of the membrane, a document (j.appl.polym.sci.2012) discloses that a composite membrane prepared by interfacial polymerization is modified by amino-functionalized cyclodextrin to improve the hydrophilicity and the anti-pollution performance of the membrane. Patent CN 102327746a discloses a porous support membrane compounded with a layer of aromatic polymer functional skin layer containing cyclodextrin by interfacial polymerization, which shows good nanofiltration desalination performance. Patents CN 106345318A and CN111359455A disclose that the cyclodextrin derivative is directly subjected to interfacial polymerization with polyacyl chloride to obtain a hydrophilic composite membrane with a contact angle of 33-45 °, which shows good nanofiltration separation performance and contamination resistance, and is used for pervaporation alcohol/water separation. Patent CN104128102A discloses that a composite membrane prepared by interfacial polymerization of an aqueous solution formed by cyclodextrin and an amine compound and an acyl chloride compound is used for nanofiltration separation of an organic solvent.

In conclusion, the above modification method is effective in improving the hydrophilicity of the membrane surface, and the chlorine resistance of the membrane can be improved by introducing a silane coupling agent. However, the operation is complicated, and the additional protective layer increases the permeation resistance of the membrane, resulting in a decrease in the water flux of the membrane.

Disclosure of Invention

Aiming at the defects, the invention provides a method for modifying a polysulfone membrane by adopting a silane coupling agent to assist cyclodextrin interfacial polymerization, so as to obtain a hydrophilic chlorine-resistant polysulfone membrane. The preparation method of the hydrophilic chlorine-resistant polysulfone membrane mainly comprises the following steps:

(1) preparation of modified liquid

Under the condition of stirring, dissolving Cyclodextrin (CD) and a silane coupling agent in water according to the mass ratio of 40: 1-5: 1 to ensure that the concentration of the cyclodextrin is 0.5-2.0 wt%, and completely dissolving to obtain a cyclodextrin water solution containing the silane coupling agent as an aqueous phase solution of interfacial polymerization. In addition, adding an organic phase monomer containing acyl chloride groups into n-hexane under the stirring condition, and fully dissolving to obtain 0.15-1.0 wt% of an n-hexane solution of an organic phase containing acyl chloride groups, wherein the n-hexane solution is used as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

And (2) immersing the fully cleaned and pretreated polysulfone ultrafiltration membrane into the water phase solution prepared in the step (1) for 5-50 min by adopting an immersion method, taking out the polysulfone ultrafiltration membrane, and then putting the polysulfone ultrafiltration membrane into the oil phase solution prepared in the step (1), so that the cyclodextrin containing the silane coupling agent and the organic phase monomer containing acyl chloride groups in the oil phase are subjected to interfacial polymerization on the surface of the polysulfone membrane.

(3) Post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization is finished, placing the modified polysulfone composite membrane obtained in the step (2) in an oven, carrying out heat treatment at the temperature of 40-110 ℃ for 15-60 min, taking out, placing in an aqueous solution with the pH value of 8-13 for 1-3 h, taking out, and cleaning with deionized water to obtain the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

Further, the polysulfone membrane is a polysulfone ultrafiltration membrane with the molecular weight cut-off of 10-100 kDa;

furthermore, the cyclodextrin is an external hydrophilic and internal hydrophobic nano-cavity structure containing a large number of hydroxyl groups, and mainly comprises alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), gamma-cyclodextrin (gamma-CD) and amino-cyclodextrin (H)₂N-CD) and hydroxypropyl- β -cyclodextrin (HP- β -CD), preferably β -CD and HP- β -CD;

further, the silane coupling agents include, but are not limited to, gamma-aminopropyltriethoxysilane (KH-550), gamma- (2, 3-glycidoxy) propyltriethoxysilane (KH-560), gamma- (methacryloyloxy) propyltriethoxysilane (KH-570), and gamma-mercaptopropyltriethoxysilane (KH-580), preferably KH-550, KH-560;

further, the organic phase monomer containing an acid chloride group used mainly includes trimesoyl chloride (TMC), isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), preferably TMC.

The hydrophilic chlorine-resistant polysulfone membrane provided by the invention is used as a filtering membrane for filtering Evans blue aqueous solution, and is cleaned and recovered by sodium hypochlorite.

The invention utilizes the inherent external hydrophilic and internal hydrophobic nanometer cavity of the cyclodextrin to provide an additional transmission channel for water molecules, and the cyclodextrin is assembled on the surface of the polysulfone membrane in an interfacial polymerization way, so that the polysulfone membrane can show better hydrophilic propertyAnd (4) sex. In addition, a silane coupling agent is introduced into the cyclodextrin, and the silane coupling agent is hydrolyzed in an alkaline solution with the pH value of 8-13, so that a Si-O-Si structure long chain containing a large number of hydrophilic groups such as hydroxyl groups can be formed, the interface effect of the cyclodextrin and acyl chloride is enhanced, and the obtained modified polysulfone membrane has good chlorine resistance and strong hydrophilicity. The method has the advantages of low cost of the used reagent, simple operation of the adopted interfacial polymerization method, no need of special conditions and environmental friendliness. As shown in figure 1, the contact angle of the polysulfone raw membrane is 92 degrees, and the contact angle of the modified membrane to water is reduced to 69 degrees. The application effects in the examples show that the flux of the polysulfone raw membrane is 5.73L/(m) when 10ppm of Evans blue aqueous solution is separated²h.MPa), the flux of the modified polysulfone membrane can reach 54.54L/(m)²h.MPa). As shown in the attached figure 2, after the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone composite membrane prepared by the invention is soaked in 10000mg/L sodium hypochlorite solution for 96 hours, the flux of the composite membrane is basically kept stable, and the retention rate of 10ppm Evans blue is still over 95 percent; moreover, as shown in figure 3, after the membrane is cleaned by sodium hypochlorite for 30min, the flux recovery rate of the modified membrane is as high as 98.9%. The result shows that the silane coupling agent assisted cyclodextrin interfacial polymerization modified polysulfone composite membrane prepared by the invention has better hydrophilicity and chlorine resistance.

Drawings

FIG. 1 is a graph of contact angles of a polysulfone organic membrane original membrane (a) and a polysulfone modified composite membrane in example 4(b) of the present invention;

FIG. 2 chlorine resistance at 10g/L aqueous solution of ClaClO of example 4 of the present invention.

Fig. 3 example 4 is the flux recovery of the polysulfone composite membrane after it has been contaminated with evans blue aqueous solution, after it has been washed with water for 30min and with sodium hypochlorite aqueous solution.

Detailed Description

The present invention will be further described with reference to the following embodiments, but the scope of the present invention is not limited to the following embodiments.

Example 1

(1) Preparation of modified liquid

Dissolving HP-beta-CD and KH-550 in water at a mass ratio of 40:1 under stirring to make the concentration of KH-550 at 0.01 wt% and the concentration of HP-beta-CD at 0.5 wt%, and dissolving uniformly to obtain HP-beta-CD aqueous solution containing KH-550 as aqueous phase solution of interfacial polymerization. In addition, adding TMC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.15 wt% TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 10kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 50min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 50 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in an oven at 40 ℃ for thermal crosslinking for 110min, then placing the modified polysulfone composite membrane in an aqueous solution with the pH of 8 for 3h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface of the modified polysulfone composite membrane is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Carrying out a water contact angle test on the prepared KH-550/HP-beta-CD polysulfone composite nanofiltration membrane to obtain a water contact angle of the modified polysulfone membrane of 79 degrees, and carrying out a nanofiltration separation performance test in a cross-flow nanofiltration device under the following test conditions: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of the Evans blue aqueous solution is 97.43%, and the water flux is 25.91L/(m²·h·MPa)。

Example 2

(1) Preparation of modified liquid

Dissolving HP-beta-CD and KH-550 in water at a mass ratio of 4:1 under stirring to make the concentration of KH-550 at 0.1 wt% and the concentration of HP-beta-CD at 1.0 wt%, and dissolving uniformly to obtain HP-beta-CD aqueous solution containing KH-550 as aqueous phase solution of interfacial polymerization. In addition, adding TMC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.5 wt% TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 50kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 20min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 20 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a 60 ℃ oven for thermal crosslinking for 30min, then placing the modified polysulfone composite membrane in a water solution with the pH of 10 for 2.0h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Carrying out water contact angle test on the prepared KH-550/HP-beta-CD polysulfone composite nanofiltration membrane, measuring that the water contact angle of the modified polysulfone membrane is 74 degrees, and carrying out nanofiltration separation performance test in a cross-flow nanofiltration device, wherein the test conditions are as follows: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of the Evans blue aqueous solution is 93.95%, and the water flux is 21.36L/(m²·h·MPa)。

Example 3

(1) Preparation of modified liquid

Dissolving HP-beta-CD and KH-550 in water at a mass ratio of 5:1 under stirring to make the concentration of KH-550 at 0.2 wt% and the concentration of HP-beta-CD at 2.0 wt%, and dissolving uniformly to obtain HP-beta-CD aqueous solution containing KH-550 as aqueous phase solution of interfacial polymerization. In addition, under the condition of stirring, adding TMC organic phase monomer into n-hexane, and fully dissolving to obtain 1.0 wt% TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 100kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 5min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 30 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a drying oven at 110 ℃ for thermal crosslinking for 15min, then placing the modified polysulfone composite membrane in an aqueous solution with the pH value of 13 for 1.0h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Carrying out a water contact angle test on the prepared KH-550/HP-beta-CD polysulfone composite nanofiltration membrane, measuring that the water contact angle of the modified polysulfone membrane is 72 degrees, and carrying out a nanofiltration separation performance test in a cross-flow nanofiltration device, wherein the test conditions are as follows: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of the Evans blue aqueous solution is 98.98%, and the water flux is 35.91L/(m²·h·MPa)。

Example 4

(1) Preparation of modified liquid

Under stirring, adding NH₂-beta-CD and KH-560 are dissolved in water at a mass ratio of 20:1 such that the concentration of KH-560 is 0.08 wt%, NH₂The concentration of the-beta-CD is 0.8 wt%, and NH containing KH-560 is obtained after uniform dissolution₂-aqueous solution of β -CD as aqueous solution for interfacial polymerization. In addition, adding a TPC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.8 wt% of TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 50kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 15min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out an interfacial reaction for 10 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a 60 ℃ oven for thermal crosslinking for 25min, then placing the modified polysulfone composite membrane in a water solution with the pH value of 11 for 1.2h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Subjecting the prepared KH-560/NH₂Carrying out a water contact angle test on the beta-CD polysulfone composite nanofiltration membrane, wherein the water contact angle of the modified polysulfone membrane is 69 degrees, and carrying out a nanofiltration separation performance test in a cross-flow nanofiltration device under the following test conditions: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of the Evans blue aqueous solution is 97.56%, and the water flux is 54.54L/(m²·h·MPa)。

Example 5

(1) Preparation of modified liquid

Dissolving gamma-CD and KH-590 in water according to the mass ratio of 10:1 under stirring to ensure that the concentration of KH-580 is 0.18 wt% and the concentration of gamma-CD is 1.2 wt%, and uniformly dissolving to obtain an aqueous solution of gamma-CD containing KH-580 as an aqueous phase solution of interfacial polymerization. In addition, adding IPC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.75 wt% of TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 60kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 28min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 26 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a 45 ℃ oven for thermal crosslinking for 35min, then placing the modified polysulfone composite membrane in a water solution with the pH of 9 for 1.8h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Carrying out water contact angle test on the prepared KH-590/gamma-CD polysulfone composite nanofiltration membrane, and testing the water contact angle of the modified polysulfone membrane to be 70 degrees, wherein the nanofiltration separation performance test is carried out in a cross-flow nanofiltration device, and the test conditions are as follows: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, and the evans blue aqueous solution is interceptedThe rate is 98.01 percent, and the water flux is 20.91L/(m)²·h·MPa)。

Example 6

(1) Preparation of modified liquid

Under the condition of stirring, dissolving beta-CD and KH-570 in water according to the mass ratio of 8:1 to ensure that the concentration of KH-570 is 0.07 wt% and the concentration of beta-CD is 1.4 wt%, and uniformly dissolving to obtain beta-CD aqueous solution containing KH-570 as aqueous phase solution of interfacial polymerization. In addition, adding TMC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.55 wt% TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 40kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 22min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 25 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a 55 ℃ oven for thermal crosslinking for 20min, then placing the modified polysulfone composite membrane in a water solution with the pH of 10.5 for 2.5h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Performing a water contact angle test on the prepared KH-570/beta-CD polysulfone composite nanofiltration membrane to obtain a water contact angle of the modified polysulfone membrane of 71 degrees, and performing a nanofiltration separation performance test in a cross-flow nanofiltration device under the following test conditions: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of Evans blue aqueous solution is 95.6%, and the water flux is 34.7L/(m²·h·MPa)。

Example 7

(1) Preparation of modified liquid

Under the condition of stirring, dissolving alpha-CD and KH-550 in water according to the mass ratio of 20:1 to ensure that the concentration of KH-550 is 0.16 wt% and the concentration of alpha-CD is 1.6 wt%, and uniformly dissolving to obtain an alpha-CD aqueous solution containing KH-550, wherein the alpha-CD aqueous solution is used as an aqueous phase solution of interfacial polymerization. In addition, adding a TPC organic phase monomer into n-hexane under the condition of stirring, and fully dissolving to obtain 0.30 wt% of TMC n-hexane solution as an oil phase solution of interfacial polymerization;

(2) silane coupling agent assisted interfacial polymerization of cyclodextrins

Fully soaking a polysulfone membrane with the molecular weight cutoff of 60kDa in deionized water, taking out, soaking in the water phase solution prepared in the step (1) for 35min, taking out, then placing in the oil phase solution prepared in the step (1), and carrying out interface reaction for 35 min;

(3) post-treatment of modified polysulfone membranes

And (3) after the interfacial polymerization reaction is finished, placing the modified polysulfone composite membrane obtained in the step (2) in a 65 ℃ oven for thermal crosslinking for 23min, then placing the modified polysulfone composite membrane in a water solution with the pH of 12.5 for 1.8h, taking out the modified polysulfone composite membrane, and washing the modified polysulfone composite membrane with deionized water until the surface is neutral, thus obtaining the silane coupling agent-assisted cyclodextrin interfacial polymerization modified polysulfone membrane.

(4) Use of modified membranes

Carrying out a water contact angle test on the prepared KH-550/alpha-CD polysulfone composite nanofiltration membrane to obtain a water contact angle of 73 degrees, and carrying out a nanofiltration separation performance test in a cross-flow nanofiltration device under the following test conditions: the feed liquid is 10.0ppm Evans blue aqueous solution, the pressure is 0.6MPa, the retention rate of the Evans blue aqueous solution is 92.6 percent, and the water flux is 30.6L/(m²·h·MPa)。