Method for preparing polyamide nanofiltration membrane based on hydrophobic amine monomer and application of membrane

Abstract

The invention discloses a method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer. The preparation method comprises the following steps: dissolving 2, 6-dimethyl piperazine in ultrapure water to form a 0.5-2.5 wt% aqueous phase solution; the preparation method comprises the following steps: dissolving 1, 3, 5-trimesoyl chloride in n-heptane to prepare a 0.1 wt% organic phase solution; and soaking the polyacrylonitrile membrane in the aqueous phase solution and the organic phase solution in sequence, and forming the polyamide layer through interfacial polymerization reaction. In the reaction process, the alkyl group of the hydrophobic amine monomer effectively reduces the diffusion rate of the monomer, and the limited diffusion kinetics effectively inhibits excessive migration of the amine monomer to an organic phase, so that the interfacial polymerization reaction is limited in a narrower region, thereby forming an ultrathin polyamide active layer with a uniform structure, and improving the performance of the polymer. And high solvent permeation flux is ensured. Meanwhile, a uniform network structure is ensured by relatively high crosslinking degree, and dye molecules can be effectively intercepted. The nanofiltration membrane prepared by the method is used for resourceful treatment of waste organic solvents in pharmacy, printing and dyeing, food industries and the like, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the preparation of nanofiltration membranes and the application of separation technology, and in particular to a method for preparing polyamide nanofiltration membranes based on hydrophobic amine monomers and the application thereof. Background Art

[0002] With the rapid development of industries like chemical, electronics, pharmaceutical, and printing, millions of tons of organic solvents enter the global environment annually through industrial emissions and waste disposal. The volatile organic compounds (VOCs) released during these waste solvent discharges not only contribute to environmental issues like ozone pollution, but also significantly increase the risk of respiratory damage and blood disorders among workers due to long-term exposure to toxic compounds like benzene and halogenated hydrocarbons. Therefore, reducing the use of organic solvents is a pressing need for industrial applications.

[0003] Compared to traditional thermal processes such as distillation, evaporation, and drying, organic solvent nanofiltration has the advantages of high efficiency, energy saving, and environmental protection, and its energy consumption is only 10% of traditional technologies. Polyamide membranes with high permeability selectivity are the core of organic solvent nanofiltration membrane technology. However, traditional polyamide membranes are prepared from planar reactive monomers with tightly stacked polymer chains, so the permeability is generally low and is limited by the "trade-off" effect between permeability and rejection rate. Optimizing membrane structure through performance optimization strategies is the key to achieving breakthroughs in the permeability of polyamide membranes. By regulating and slowing the diffusion rate of amine monomers through the steric hindrance effect of the substituents of hydrophobic amine monomers, ultra-thin polyamide membranes and high cross-linking degrees are achieved, while also improving the permeability and selectivity of polyamide nanofiltration membranes. Summary of the Invention

[0004] In response to the above-mentioned prior art, the present invention provides a method for preparing polyamide nanofiltration membranes based on hydrophobic amine monomers. The preparation method utilizes the steric effect of the hydrophobic amine monomer substituents to slow down the monomer diffusion rate to regulate the interfacial polymerization process, in order to reduce the membrane thickness, increase the cross-linking degree, and at the same time improve the membrane selectivity and permeability.

[0005] In order to solve the above technical problems, the present invention proposes a method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer, which mainly includes: dissolving 2,6-dimethylpiperazine in ultrapure water to prepare an aqueous solution with a mass percentage of 0.5-2.5%; dissolving 1,3,5-benzenecarboxylic acid chloride in n-heptane to prepare an organic phase solution with a mass percentage of 0.1%; using a polyacrylonitrile membrane as a base membrane, soaking the base membrane in the above aqueous phase solution and organic phase solution in sequence, and reacting the amino groups in the aqueous phase solution with the acyl chloride groups in the organic phase solution at the phase interface to prepare a polyamide nanofiltration membrane. The specific steps are as follows:

[0006] Step 1) dissolving 2,6-dimethylpiperazine in ultrapure water to prepare an aqueous solution with a mass percentage of 0.5-2.5%; dissolving 1,3,5-trimesoyl chloride in n-heptane to prepare an organic solution with a mass percentage of 0.1%;

[0007] Step 2) The polyacrylonitrile membrane is fixed in a plastic mold, and the aqueous solution is added to the mold. The amount of the aqueous solution is proportional to the area of ​​the polyacrylonitrile membrane, 10 mL / 25 cm 2 After soaking for 5 minutes, take out the polyacrylonitrile membrane and remove the surface liquid;

[0008] Step 3) The polyacrylonitrile membrane after the soaking reaction in step 2) is fixed back into the mold, and the organic phase solution is added into the mold. The amount of the organic phase solution is proportional to the area of ​​the polyacrylonitrile membrane, and the ... 2 After soaking for 4 to 8 minutes, the organic phase solution was poured out and the surface was rinsed with n-heptane, and the membrane was placed in an oven for thermal curing reaction. The thermal curing reaction time was 5 to 9 minutes to obtain a polyamide nanofiltration membrane.

[0009] Furthermore, the method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to the present invention comprises:

[0010] Preferably, in step 1), the mass percentage of 2,6-dimethylpiperazine in the aqueous solution is 1.5%.

[0011] In step 2), the molecular weight cut-off of the polyacrylonitrile membrane is 10 kDa, and the plastic mold has a size of 5x5 cm 2 The exposed area of ​​basement membrane.

[0012] In step 3), the soaking reaction time of the organic phase solution is 6 minutes, and the thermal curing reaction time is 7 minutes.

[0013] The polyamide nanofiltration membrane prepared by the present invention is stored in ultrapure water.

[0014] The polyamide nanofiltration membrane prepared according to the method of the present invention has an ethanol permeability of 71.96 to 318.89 L m -2 h-1bar -1 The Evans blue (EB) rejection rate is 89.08% to 98%. The polyamide nanofiltration membrane can be applied to organic solvent nanofiltration.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The preparation method of the present invention utilizes the steric effect caused by the alkyl substituent of the hydrophobic amine monomer to control the monomer diffusion rate. This limited mass transfer characteristic effectively delays the interfacial polymerization reaction rate and promotes the formation of an ultrathin selective layer with a thickness of about 13.79 nm (Example 1, Figure 2 ) and constructed a more regular polymer network structure.

[0017] (2) The polyamide membrane (2,6-DMPIP-TMC membrane) prepared based on 2,6-dimethylpiperazine (2,6-DMPIP) exhibited significantly enhanced permeability, with a permeability of 151.05 L m -2 h-1bar -1 The 2,6-DMPIP-TMC membrane exhibited a molecular weight cut-off (MWCO) of 582 Da, which was 10.5 times and 43.6 times higher than those of polyamide membranes based on 2,2-dimethylpiperazine (2,2-DMPIP) or 2-ethylpiperazine (2-EPIP) systems, respectively.

[0018] In summary, in the preparation method of the present invention, the alkyl group of the hydrophobic amine monomer effectively reduces the monomer's diffusion rate. This restricted diffusion dynamics effectively inhibits excessive migration of the amine monomer into the organic phase, confining the interfacial polymerization reaction to a narrower region. This results in the formation of an ultrathin and structurally uniform polyamide active layer, ensuring high solvent permeation flux. Furthermore, the high degree of cross-linking ensures a uniform network structure, effectively trapping dye molecules, with a molecular weight cut-off of only 582 Da. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the formation mechanism of the polyamide membrane prepared based on the hydrophobic amine monomer according to the present invention;

[0020] Figure 2 This is a transmission electron micrograph of the 2,6-DMPIP-TMC-1 membrane prepared in Example 1;

[0021] Figure 3 This is a transmission electron micrograph of the 2,2-DMPIP-TMC membrane prepared in Comparative Example 1;

[0022] Figure 4 This is a transmission electron micrograph of the 2-EPIP-TMC film prepared in Comparative Example 2;

[0023] Figure 5 This is a scanning electron microscope photograph of the 2-EPIP-TMC membrane prepared in Comparative Example 2;

[0024] Figure 6 Graph showing the ethanol permeability of the membranes prepared in Example 1 and Comparative Examples 1-2;

[0025] Figure 7 is a relationship diagram between the permeability of the 2,6-DMPIP-TMC-1 membrane prepared in Example 1 and the inverse of the viscosity of the organic solvent;

[0026] Figure 8 The dye retention curves of the membranes prepared in Example 1 and Comparative Examples 1-2 are shown. DETAILED DESCRIPTION

[0027] The design concept of the method for preparing polyamide nanofiltration membrane based on poly-organic cage intermediate layer is as follows: dissolving hydrophobic amine monomer in ultrapure water to form an aqueous phase solution; dissolving 1,3,5-trimethylbenzenecarboxylic acid chloride (TMC) in n-heptane to form an organic phase solution; soaking the polyacrylonitrile-based membrane with the above aqueous phase solution and organic phase solution in sequence, and the amino group in the amine monomer reacts with the acyl chloride group of TMC at the phase interface to prepare the polyamide nanofiltration membrane, such as Figure 1 As shown in the figure, the steric hindrance effect of the substituents regulates the interfacial polymerization kinetics, slowing the monomer diffusion rate and enabling more orderly diffusion to the reaction interface, which helps to form a uniform, defect-free, highly cross-linked polyamide membrane. While improving selectivity, the reduced thickness of the polyamide membrane significantly shortens the mass transfer channels, significantly improving solvent permeability. The result is a high-performance polyamide nanofiltration membrane with both enhanced selectivity and permeability.

[0028] Through systematic comparative analysis of piperazine derivatives with the same molecular weight but different configurations (2,6-DMPIP, 2,2-DMPIP, and 2-EPIP), it was found that the heptane phase diffusion coefficient of 2,6-DMPIP was significantly lower than that of 2,2-DMPIP and 2-EPIP due to the strong steric effect formed by the ortho-methyl group, which significantly delayed the interfacial reaction process. This kinetic regulation mechanism reduced the thickness of the selective layer to 13.79nm and formed a highly regular cross-linked network. The resulting 2,6-DMPIP-TMC membrane exhibited a 151.05L m -2 h-1bar -1 The ultra-high permeability and the precise screening ability of the highly cross-linked network achieve a MWCO of 582Da, providing a systematic solution of molecular design-mass transfer regulation-performance optimization for the controllable construction of organic solvent nanofiltration membranes.

[0029] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention and do not limit the scope of protection of the claims of this application.

[0030] The separation performance of the prepared polyamide nanofiltration membrane is evaluated mainly by characterizing two characteristic parameters: dye retention rate and solvent permeability.

[0031] Retention rate calculation formula: R = (1-C p / C f)×100%, where R represents the retention rate, C p and C f are the dye concentrations (ppm) in the permeate and feed solutions, respectively. Unless otherwise specified, the feed solution is a 50 ppm Evans blue (EB) ethanol solution.

[0032] Solvent permeability (L m-2h -1 bar -1 ) is defined as: under certain operating pressure conditions, the volume of solvent passing through a unit effective membrane area per unit pressure and unit time. The test pressure is 0.5 bar.

[0033] Example 1

[0034] The preparation steps of polyamide nanofiltration membrane based on hydrophobic amine monomer 2,6-DMPIP are as follows:

[0035] Step 1) Pretreatment of the polyacrylonitrile-based membrane: The polyacrylonitrile-based membrane was washed three times with ultrapure water, dried at room temperature, and then fixed in a plastic mold;

[0036] Step 2) Soaking in aqueous solution: dissolve 2,6-DMPIP in ultrapure water to prepare a 1.5% by mass amine monomer solution, and add the aqueous solution to the mold in step 1). The amount of the aqueous solution is proportional to the area of ​​the polyacrylonitrile-based membrane, 10 mL / 25 cm 2 After soaking for 5 minutes, remove and remove the surface liquid, and again fix the polyacrylonitrile base film after soaking the reaction to the mold;

[0037] Step 3) Synthesize polyamide by reaction: dissolve TMC in n-heptane to prepare an organic phase solution with a mass percentage of 0.1%, and add the organic phase solution to the mold fixed with the polyacrylonitrile base film treated in step 2). The amount of the organic phase solution is proportional to the area of ​​the polyacrylonitrile base film, 10 mL / 25 cm 2 After soaking for 6 minutes, the organic phase solution was poured out and the surface was rinsed with n-heptane, and the membrane was placed in an oven for thermal curing reaction. The thermal curing time was 7 minutes to obtain a polyamide nanofiltration membrane, which was recorded as 2,6-DMPIP-TMC-1 membrane. Figure 2 This is a transmission electron micrograph of the active layer of the 2,6-DMPIP-TMC-1 membrane. The membrane thickness is only 13.79 nm.

[0038] The test showed that the MWCO of the 2,6-DMPIP-TMC-1 membrane prepared in Example 1 was 582 Da, the EB rejection rate was 96.43%, and the ethanol permeability was 151.05 L m - 2h -1 bar -1 , as shown in Table 1.

[0039] Example 2

[0040] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer 2,6-DMPIP is basically the same as that in Example 1, except that in step 3), the heat curing time is changed from 7 min to 5 min. The final polyamide nanofiltration membrane is recorded as 2,6-DMPIP-TMC-2 membrane.

[0041] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-2 membrane prepared in Example 2 was 93.33%, and the ethanol permeability was 255.46 L m -2 h -1 bar -1 , as shown in Table 1.

[0042] Example 3

[0043] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer 2,6-DMPIP is basically the same as that in Example 1, except that in step 3), the heat curing time is changed from 7 min to 9 min. The final polyamide nanofiltration membrane is recorded as 2,6-DMPIP-TMC-3 membrane.

[0044] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-3 membrane prepared in Example 3 was 98%, and the ethanol permeability was 71.96 L m - 2h -1 bar -1 , as shown in Table 1.

[0045] Example 4

[0046] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer is basically the same as that in Example 1, except that in step 3), the soaking reaction time is changed from 7 min to 4 min. The final polyamide nanofiltration membrane is recorded as 2,6-DMPIP-TMC-4 membrane.

[0047] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-4 membrane prepared in Example 4 was 91.38%, and the ethanol permeability was 171.15 L m - 2h -1 bar -1 , as shown in Table 1.

[0048] Example 5

[0049] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer is basically the same as that in Example 1, except that in step 3), the soaking reaction time is changed from 7 min to 8 min. The polyamide nanofiltration membrane finally obtained is recorded as 2,6-DMPIP-TMC-5 membrane.

[0050] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-5 membrane prepared in Example 5 was 97.21%, and the ethanol permeability was 126.53 L m - 2h -1 bar -1 , as shown in Table 1.

[0051] Example 6

[0052] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer is basically the same as that in Example 2, except that in step 2), the concentration of 2,6-DMPIP in the aqueous solution is changed from 1.5% to 0.5%. The final polyamide nanofiltration membrane is recorded as 2,6-DMPIP-TMC-6 membrane.

[0053] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-6 membrane prepared in Example 6 was 89.08%, and the ethanol permeability was 318.89 L m - 2h -1 bar -1 , as shown in Table 1.

[0054] Example 7

[0055] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer is basically the same as that in Example 2, except that in step 2), the concentration of 2,6-DMPIP in the aqueous solution is changed from 1.5% to 2.5%. The final polyamide nanofiltration membrane is recorded as 2,6-DMPIP-TMC-7 membrane.

[0056] The test showed that the EB rejection rate of the 2,6-DMPIP-TMC-7 membrane prepared in Example 7 was 96.5%, and the ethanol permeability was 153.25 L m - 2h -1 bar -1 , as shown in Table 1.

[0057] Comparative Example 1

[0058] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer 2,2-DMPIP is basically the same as that in Example 1, except that the amine monomer described in step 2) is changed from 2,6-DMPIP to 2,2-DMPIP. The final polyamide nanofiltration membrane is recorded as 2,2-DMPIP-TMC membrane. Figure 3 This is a transmission electron micrograph of the active layer of the 2,2-DMPIP-TMC membrane. The membrane thickness is 48.28 nm.

[0059] The test showed that the MWCO of the 2,2-DMPIP-TMC membrane prepared in Comparative Example 1 was 525 Da, the EB rejection rate was 99.66%, and the ethanol permeability was 13.16 L m - 2h -1 bar -1 , as shown in Table 1.

[0060] Comparative Example 2

[0061] The preparation process of the polyamide nanofiltration membrane based on the hydrophobic amine monomer 2-EPIP is basically the same as that in Example 1, except that the amine monomer described in step 2) is changed from 2,6-DMPIP to 2-EPIP. The final polyamide nanofiltration membrane is recorded as 2-EPIP-TMC membrane. Figure 4 This is a transmission electron microscope photograph of the active layer of the 2-EPIP-TMC membrane. The membrane thickness is 59.31 nm. Figure 5 is a scanning electron microscope photograph of the membrane.

[0062] The results show that the MWCO of the 2-EPIP-TMC membrane prepared in Comparative Example 2 is 488 Da, the EB rejection rate is 99.8%, and the ethanol permeability is 3.39 L m - 2h -1 bar -1 , as shown in Table 1.

[0063] Table 1 Test data related to Examples 1 to 7 and Comparative Examples 1 to 2

[0064]

[0065] Figure 6 The ethanol permeability diagram of the membranes prepared in Example 1 and Comparative Examples 1-2 shows that the polyamide membrane prepared based on 2,6-DMPIP exhibits significantly enhanced permeability, with a permeability of 151.05 L m -2 h-1bar -1 , compared with 2,2-DMPIP (13.16L m -2 h-1bar -1 ) and 2-EPIP (3.39 L m -2 h-1bar -1 ) systems were increased by 10.5 times and 43.6 times respectively.

[0066] Figure 7 The relationship between the permeability of the 2,6-DMPIP-TMC-1 membrane prepared in Example 1 and the inverse of the organic solvent viscosity is shown. There is a significant negative correlation between the solvent permeability (J) and the dynamic viscosity (η) (J∝η -1), which is consistent with the prediction trend of the modified Hagen-Poiseuille equation. The ultrathin active layer greatly reduces the path resistance of solvent transport.

[0067] Figure 8 The dye retention curves of the membranes prepared in Example 1 and Comparative Examples 1-2 show a gradient difference in MWCO: 582 Da, 525 Da, and 488 Da, respectively. This selectivity difference can be attributed to the gradient change in the thickness of the active layer (13.79 nm → 48.28 nm → 59.31 nm).

[0068] The present invention provides a method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer. The materials used are easy to synthesize, the preparation process is simple, and the operation is relatively convenient. The membrane separation performance is mainly evaluated by the dye retention rate, molecular weight cutoff and ethanol permeability of the membrane. Among them, the molecular weight cutoff is the core indicator for evaluating membrane separation performance. Compared with the dye retention rate alone, it can more comprehensively reflect the actual separation ability of the membrane in a complex system. The current mainstream polyamide membrane has been applied on a large scale in the field of water treatment due to its controllable construction of ultra-thin separation layer and the maturity of the interfacial polymerization process. However, its design paradigm is highly dependent on the aqueous phase reaction environment - by introducing hydrophilic functional groups such as carboxylic acid groups and hydroxyl groups to optimize the water molecule transmission channel, it leads to significant performance attenuation in the organic solvent system. This limitation is due to the swelling effect of organic solvents on the membrane structure, the solute-solvent polarity mismatch and the low compatibility of traditional mass transfer channels with non-polar molecules.

[0069] The preparation method of the present invention utilizes alkyl substituents to enhance the hydrophobicity of the monomer, making it suitable for use in organic solvent systems. Simultaneously, the steric hindrance effect of the substituents regulates the interfacial polymerization kinetics, slowing the monomer diffusion rate and enabling more orderly diffusion to the reaction interface, thereby facilitating the formation of a uniform, defect-free, highly cross-linked polyamide membrane. While enhancing selectivity, the reduced thickness of the polyamide membrane significantly shortens the mass transfer pathway, significantly increasing solvent permeability. Ultimately, a high-performance polyamide nanofiltration membrane with both enhanced selectivity and permeability is achieved.

[0070] In the present invention, by comparing Examples 1 to 7 and Comparative Examples 1 to 2, it can be concluded that by rationally adjusting the membrane conditions, the introduction of hydrophobic monomers will greatly improve the selectivity and permeability of the membrane. The alkyl group of the hydrophobic amine monomer effectively reduces the diffusion rate of the monomer. This restricted diffusion dynamics effectively inhibits the excessive migration of the amine monomer to the organic phase, so that the interfacial polymerization reaction is confined to a narrower area, thereby forming an ultra-thin and structurally uniform polyamide active layer, ensuring a high solvent permeation flux. At the same time, a higher degree of cross-linking ensures a uniform network structure, which can effectively intercept dye molecules and exhibit excellent size screening capabilities. The nanofiltration membrane prepared by the present invention is used for the resource treatment of waste organic solvents in the pharmaceutical, printing and dyeing, and food industries, and has broad application prospects.

[0071] 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 improvements and changes without departing from the purpose of the present invention, which are all protected by the present invention.

Claims

1. A method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer, characterized in that: 2,6-Dimethylpiperazine is dissolved in ultrapure water to prepare an aqueous solution with a mass percentage of 0.5-2.5%; 1,3,5-Trimethylol chloride is dissolved in n-heptane to prepare an organic solution with a mass percentage of 0.1%; a polyacrylonitrile membrane is used as a base membrane, and the base membrane is soaked in the above-mentioned aqueous solution and organic solution in sequence, and the amino groups in the aqueous solution react with the acyl chloride groups in the organic solution at the phase interface to prepare a polyamide nanofiltration membrane.

2. The method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to claim 1, characterized in that: The following steps are involved: Step 1) dissolving 2,6-dimethylpiperazine in ultrapure water to prepare an aqueous solution with a mass percentage of 0.5-2.5%; dissolving 1,3,5-trimesoyl chloride in n-heptane to prepare an organic solution with a mass percentage of 0.1%; Step 2) The polyacrylonitrile membrane is fixed in a plastic mold, and the aqueous solution is added to the mold. The amount of the aqueous solution is proportional to the area of ​​the polyacrylonitrile membrane, 10 mL / 25 cm 2 After soaking for 5 minutes, take out the polyacrylonitrile membrane and remove the surface liquid; Step 3) The polyacrylonitrile membrane after the soaking reaction in step 2) is fixed back into the mold, and the organic phase solution is added into the mold. The amount of the organic phase solution is proportional to the area of ​​the polyacrylonitrile membrane, and the ... 2 After soaking for 4 to 8 minutes, the organic phase solution was poured out and the surface was rinsed with n-heptane, and the membrane was placed in an oven for thermal curing reaction. The thermal curing reaction time was 5 to 9 minutes to obtain a polyamide nanofiltration membrane.

3. The method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to claim 2, characterized in that: In step 1), the mass percentage of 2,6-dimethylpiperazine in the aqueous solution is 1.5%.

4. The method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to claim 2, characterized in that: In step 2), the molecular weight cut-off of the polyacrylonitrile membrane is 10 kDa, and the plastic mold has a size of 5x5 cm 2 The exposed area of ​​basement membrane.

5. The method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to claim 2, wherein: In step 3), the soaking reaction time of the organic phase solution is 6 minutes, and the thermal curing reaction time is 7 minutes.

6. The method for preparing a polyamide nanofiltration membrane based on a hydrophobic amine monomer according to claim 2, characterized in that: The prepared polyamide nanofiltration membrane was stored in ultrapure water.

7. A polyamide nanofiltration membrane based on a hydrophobic amine monomer, characterized in that: The polyamide nanofiltration membrane prepared by the method according to any one of claims 1 to 6 has an ethanol permeability of 71.96 to 318.89 L m -2 h-1bar -1 The Evans blue (EB) retention rate is 89.08% to 98%.

8. The use of the polyamide nanofiltration membrane based on the hydrophobic amine monomer as claimed in claim 7, characterized in that: The polyamide nanofiltration membrane is applied to organic solvent nanofiltration.

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