An ionic liquid-based highly permeable spiral ultrafiltration membrane and its preparation method

Abstract

The present invention relates to a high-permeability spiral ultrafiltration membrane based on ionic liquid and a preparation method thereof, belonging to the technical field of spiral ultrafiltration membrane preparation. First, an aqueous solution containing m-phenylenediamine, ionic liquid, camphorsulfonic acid and triethylamine is poured onto the surface of a polysulfone ultrafiltration membrane. After standing, the residual aqueous solution on the surface is removed to obtain Membrane I after treating the polysulfone ultrafiltration membrane with the aqueous solution. Then, an organic solution containing trimesoyl chloride is poured onto the surface of Membrane I. After standing, the residual organic solution on the surface is removed to obtain Membrane II after treating Membrane I with the organic solution. Finally, after Membrane II is drained, heat-treated and rinsed with deionized water in sequence, a high-permeability spiral ultrafiltration membrane is obtained. The present invention introduces imidazolium-based ionic liquid, narrows the pore size distribution of the spiral ultrafiltration membrane, and simultaneously improves the permeability and selectivity of the membrane, and is applicable to fields such as the food industry, pharmaceuticals and biological products, and the printing and dyeing textile industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of spiral ultrafiltration membranes, and particularly relates to the preparation of a highly permeable spiral ultrafiltration membrane based on ionic liquids. Background Art

[0002] Membrane separation technology is widely used in fields such as the food industry (desalination of soy sauce / condiments), pharmaceuticals (purification of antibiotics), biological products (desalination of polypeptides / oligonucleotides), and the printing and dyeing industry (separation of dyes / inorganic salts). It has the advantages of high selectivity and low energy consumption in the separation of small organic molecules / inorganic salts. However, the type of membrane needs to be selected according to the target molecular weight, salt type, and general performance comparison. Although traditional ultrafiltration membranes can improve the rejection rate by changing the pore size or increasing the thickness of the active layer (such as achieving precise screening of molecular weights from 10 - 100 kDa), it will lead to an increase in the permeation resistance index, a flux decline of up to 40 - 60%, and the dense structure is prone to exacerbate concentration polarization, further weakening the effective mass transfer driving force. Therefore, the development of highly permeable and highly selective separation membranes is a development trend to meet the process requirements of "high-throughput precise separation of small organic molecules and inorganic salts".

[0003] To improve the permeability and separation performance of the separation membrane for small organic molecules / inorganic salts in wastewater, common modification methods include using new monomers, adding competitive reaction monomers, and using porous materials to assist interfacial polymerization (IP) reactions to improve the performance of the membrane. However, the separation membranes prepared by the above methods usually have the following problems: 1) The competition of multiple monomers will inhibit the occurrence of the main reaction, resulting in a relatively loose or even defective selective layer, affecting the separation effect. 2) Commonly used porous materials are mostly metal-organic frameworks (MOFs), and it is difficult to achieve a certain degree of tightness in cross-linking with the membrane, and they are prone to fall off, resulting in relatively poor long-term operation stability of the membrane.

[0004] Spiral ultrafiltration membranes are commonly used for the separation of small organic molecules with molecular weights greater than 500 Da and inorganic salts, such as the separation of dyes / inorganic salts, antibiotics / inorganic salts, soy sauce / inorganic salts, etc. And spiral ultrafiltration membranes are prepared by the interfacial polymerization method without introducing new monomers and porous materials, and can maintain a certain stability during long-term operation. However, although spiral ultrafiltration membranes have the screening performance for small organic molecules / inorganic salts, there is still a "seesaw" problem that it is difficult to balance permeability and selectivity. Therefore, an important object of the present invention is to prepare a new type of spiral ultrafiltration membrane with high permeability and high selectivity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a highly permeable spiral ultrafiltration membrane based on ionic liquids and its preparation method that can simultaneously improve the permeation performance and separation performance.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid, comprising the following steps:

[0007] S1. Pour an aqueous solution containing m-phenylenediamine, ionic liquid, camphorsulfonic acid and triethylamine onto the surface of a polysulfone ultrafiltration membrane. After standing, remove the residual aqueous solution on the surface to obtain Membrane I after treating the polysulfone ultrafiltration membrane with the aqueous solution;

[0008] S2. Pour an organic solution containing trimesoyl chloride onto the surface of Membrane I obtained in step S1. After standing, remove the residual organic solution on the surface to obtain Membrane II after treating Membrane I with the organic solution;

[0009] S3. After draining, heat-treating and rinsing with deionized water in sequence the Membrane II obtained in step S2, a high-permeability spiral ultrafiltration membrane is obtained.

[0010] Further, in step S1, the ionic liquid is an imidazolium-based ionic liquid.

[0011] Further, the imidazolium-based ionic liquid is one or more of 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium bromide.

[0012] Further, in step S1, the aqueous solvent in the aqueous solution is deionized water.

[0013] Further, in step S1, the mass fraction of m-phenylenediamine is 0.03 - 0.1 wt.%; the mass fraction of camphorsulfonic acid is 2.5 wt.%; the mass fraction of triethylamine is 1.5 wt.%; the mass fraction of the ionic liquid is 20 - 50 wt.%.

[0014] Further, in step S1, the standing time is 10 - 60 s; in step S2, the standing time is 30 - 90 s.

[0015] Further, in step S2, the mass fraction of trimesoyl chloride is 0.003 - 0.01 wt.%.

[0016] Further, in step S2, the organic solvent in the organic solution is n-hexane.

[0017] Further, in step S3, after draining Membrane II, it is placed in a vacuum drying oven. The heat treatment temperature is 60 - 100 °C, the heat treatment time is 1 - 5 min, the surface is rinsed with deionized water multiple times and soaked in deionized water to obtain a high-permeability spiral ultrafiltration membrane.

[0018] Another object of the present invention is to provide an ionic liquid-based high-permeability spiral ultrafiltration membrane obtained by a preparation method of an ionic liquid-based high-permeability spiral ultrafiltration membrane.

[0019] Furthermore, the rejection rate of the high-permeability spiral ultrafiltration membrane for Congo red can reach 99.0% under the condition of 0.5 MPa, the rejection rate of sodium chloride is 1.06%, and the permeation flux can reach 371.2 L m -2 h -1 。

[0020] Due to the adoption of the above technical solution, it can be seen that the present invention uses imidazolium-based ionic liquid as an aqueous phase additive in the interfacial polymerization reaction. Through the π-π interaction between the imidazolium-based ionic liquid and m-phenylenediamine, the diffusion rate of m-phenylenediamine (MPD) in the interfacial polymerization reaction is slowed down, the dispersion uniformity of MPD is improved, the pore size is optimized, the structural morphology of aromatic polyamide is adjusted, and a high-permeability spiral ultrafiltration membrane with excellent permeation performance and separation performance is prepared.

[0021] In summary, the beneficial effects of the present invention are as follows:

[0022] (1) The preparation method is simple and easy to realize industrialization. As an aqueous phase additive, the imidazolium-based ionic liquid improves the membrane separation performance without participating in the interfacial polymerization reaction. Compared with other modification methods, the operation is simple and no additional production processes and equipment are required.

[0023] (2) The ionic liquid is not likely to cause damage to the polyamide separation layer and leakage of the bottom membrane - polysulfone ultrafiltration membrane. Introducing the ionic liquid into the aqueous phase, compared with conventional modification methods such as selecting new monomers, adding competing reaction monomers, and using porous materials to assist the IP reaction, the advantage is that the ionic liquid acts from the inside of the IP reaction and does not participate in the IP reaction, effectively avoiding problems such as low crosslinking degree, easy shedding, and low separation efficiency of the added materials and the membrane.

[0024] (3) The ionic liquid itself may act as a template agent to guide the orderly arrangement of polymer chains, forming a more regular pore structure or surface morphology, thereby having a beneficial effect on the permeation performance and separation performance of the spiral ultrafiltration membrane.

[0025] (4) The imidazole ring of the imidazolium-based ionic liquid can produce π-π interaction with the benzene ring of MPD, adjust the diffusion rate of the aqueous phase monomer, and thus construct an ionic liquid-MPD film to optimize the pore size.

[0026] (5) The ionic liquid can change the viscosity of the aqueous phase and adjust the microscopic pore structure of the membrane through the self-assembly effect, enhancing the permeation performance of the membrane.

[0027] (6) The highly permeable spiral ultrafiltration membrane of the present invention can be used in the processes of soy sauce / condiment desalination, antibiotic purification, polypeptide / oligonucleotide desalination, dye / inorganic salt separation, etc. Description of the Drawings

[0028] The present invention will be specifically described below with reference to the drawings and in conjunction with examples. The advantages and implementation manners of the present invention will become more obvious. The content shown in the drawings is only for the explanation of the present invention and does not constitute any limitation to the present invention in any sense. In the drawings:

[0029] Figure 1 is the infrared spectrum diagram of the examples and comparative examples of the present invention.

[0030] Figure 2 is the mean square displacement curve (MSD) diagram of Comparative Example 1 of the present invention.

[0031] Figure 3 is the MSD diagram of Comparative Example 2 of the present invention.

[0032] Figure 4 is the MSD diagram of Example 3 of the present invention.

[0033] Figure 5 is the surface scanning electron microscope diagram of Comparative Example 1 of the present invention.

[0034] Figure 6 is the surface scanning electron microscope diagram of Comparative Example 2 of the present invention.

[0035] Figure 7 is the surface scanning electron microscope diagram of Example 1 of the present invention.

[0036] Figure 8 is the surface scanning electron microscope diagram of Example 2 of the present invention.

[0037] Figure 9 is the surface scanning electron microscope diagram of Example 3 of the present invention.

[0038] Figure 10 is the surface scanning electron microscope diagram of Example 4 of the present invention. Detailed Embodiments

[0039] In order to enable those skilled in the art of the present technology to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the best embodiments.

[0040] In the following examples and comparative examples:

[0041] The polysulfone ultrafiltration membrane is purchased from Qicheng (Jiangsu) Purification Technology Co., Ltd., and the pure water permeation flux is 500 - 600 L·m -2 ·h -1 ·bar -1, the retention rate of bovine serum albumin was 90.0 - 90.1%;

[0042] Trimesoyl chloride (TMC), analytical pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0043] m-Phenylenediamine (MPD), analytical pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0044] n-Hexane, analytical pure, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0045] Triethylamine, analytical pure, purchased from Tianjin Kemiou Co., Ltd.;

[0046] Camphorsulfonic acid, purchased from Shanghai TCI Chemical Industry Development Co., Ltd.;

[0047] 1-Hexyl-3-methylimidazolium chloride (C6mimCl), purity 98 wt.%, purchased from Macklin Biochemical Co., Ltd., China;

[0048] 1-Ethyl-3-methylimidazolium chloride (C2mimCl), purity 98 wt.%, purchased from Macklin Biochemical Co., Ltd., China;

[0049] 1-Butyl-3-methylimidazolium chloride (C4mimCl), purity 97 wt.%, purchased from Macklin Biochemical Co., Ltd., China;

[0050] 1-Octyl-3-methylimidazolium chloride (C8mimCl), purity 97 wt.%, purchased from Macklin Biochemical Co., Ltd., China;

[0051] 1-Hexyl-3-methylimidazolium bromide (C6mimBr), purity 98 wt.%, purchased from Macklin Biochemical Co., Ltd., China;

[0052] Congo red (CR), analytical pure, purchased from Tianjin Guangfu Fine Chemical Research Institute;

[0053] Sodium chloride (NaCl), analytical pure, purchased from Macklin Biochemical Co., Ltd., China.

[0054] Example 1:

[0055] A preparation method of an ionic liquid-based highly permeable spiral ultrafiltration membrane, comprising the following steps:

[0056] S1. Take out the polysulfone ultrafiltration membrane from deionized water, fix it on a self-made organic framework, drain the water droplets on the surface of the polysulfone ultrafiltration membrane, and gently absorb the water droplets on the back non-woven fabric. The polysulfone ultrafiltration membrane serves as the bottom membrane. Pour an aqueous solution containing m-phenylenediamine, ionic liquid (1-hexyl-3-methylimidazolium chloride), camphorsulfonic acid, and triethylamine onto the surface of the polysulfone ultrafiltration membrane. After standing for 30 s, pour out the excess aqueous solution, and roll it with a rubber rod to remove the residual aqueous solution on the surface, obtaining Membrane I after treating the polysulfone ultrafiltration membrane with the aqueous solution.

[0057] Among them, the mass fraction of m-phenylenediamine is 0.05 wt.%; the mass fraction of camphorsulfonic acid is 2.5 wt.%; the mass fraction of triethylamine is 1.5 wt.%; the mass fraction of ionic liquid (1-hexyl-3-methylimidazolium chloride) is 20 wt.%.

[0058] S2. Pour a n-hexane solution containing trimesoyl chloride onto the surface of Membrane I obtained in Step S1. After standing and reacting for 60 s, remove the residual organic phase solution on the surface, obtaining Membrane II after treating Membrane I with the organic solution.

[0059] Among them, the mass fraction of trimesoyl chloride is 0.005 wt.%.

[0060] S3. After draining Membrane II obtained in Step S2, place it in a vacuum drying oven and heat-treat it at 60 °C for 3 min. Then rinse the surface with deionized water multiple times and soak it in deionized water to obtain a high-permeability spiral ultrafiltration membrane.

[0061] Example 2:

[0062] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In Step S1, the mass percentage of ionic liquid (1-hexyl-3-methylimidazolium chloride) is 30 wt.%, and the rest is the same as in Example 1.

[0063] Example 3:

[0064] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In Step S1, the mass percentage of ionic liquid (1-hexyl-3-methylimidazolium chloride) is 40 wt.%, and the rest is the same as in Example 1.

[0065] Example 4:

[0066] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In Step S1, the mass percentage of ionic liquid (1-hexyl-3-methylimidazolium chloride) is 50 wt.%, and the rest is the same as in Example 1.

[0067] Comparative Example 1:

[0068] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In step S1, the mass percentage of the ionic liquid (1-hexyl-3-methylimidazolium chloride) is 0 wt.%, and the rest is the same as in Example 1.

[0069] Comparative Example 2:

[0070] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In step S1, the mass percentage of the ionic liquid (1-hexyl-3-methylimidazolium chloride) is 10 wt.%, and the rest is the same as in Example 1.

[0071] Comparative Example 3:

[0072] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In step S1, the mass percentage of the ionic liquid (1-hexyl-3-methylimidazolium chloride) is 60 wt.%, and the rest is the same as in Example 1.

[0073] Comparative Example 4:

[0074] A preparation method of a high-permeability spiral ultrafiltration membrane based on ionic liquid. In step S1, the mass percentage of the ionic liquid (1-hexyl-3-methylimidazolium chloride) is 70 wt.%, and the rest is the same as in Example 1.

[0075] Performance test:

[0076] The separation performance of the high-permeability spiral ultrafiltration membranes prepared in Examples 1 to 4 and the spiral ultrafiltration membranes prepared in Comparative Examples 1 to 4 was tested using a cross-flow filtration device.

[0077] The membrane samples were placed in 3 parallel filtration units, and the effective area of the membrane cell was 23.76 cm 2 . The feed liquid used for testing the membrane permeation selectivity was a Congo red solution of 0.1 ± 0.001 g / L and a sodium chloride solution of 2 ± 0.001 g / L; the test temperature and pressure were 25 ± 1 °C and 0.5 MPa, respectively. The concentrations of the dye and salt in the feed liquid and permeate were measured using a UV spectrophotometer and a conductivity meter, respectively.

[0078] The permeation flux is:

[0079]

[0080] In the formula, is the water permeation flux, with the unit of L·m -2 ·h -1 ; A is the effective membrane area, with the unit of m 2 ; is the amount of permeated water collected within a certain time T, with the unit of L; T is the time, with the unit of h.

[0081] The sodium chloride rejection rate is:

[0082]

[0083] Wherein, is the salt rejection rate, in %; C p is the NaCl concentration of the permeate, in mg / L; C f is the NaCl concentration of the feed liquid, in mg / L.

[0084] The Congo red rejection rate is:

[0085]

[0086] Wherein, is the dye rejection rate, in %; is the CR concentration of the permeate, in mg / L; is the CR concentration of the feed liquid, in mg / L.

[0087] The permeate flux enhancement rate is:

[0088]

[0089] Wherein, is the permeate flux enhancement rate, in %; is the water permeate flux of Examples 1 to 4 or Comparative Examples 2 to 4, in L·m -2 ·h -1 ; is the water permeate flux of Comparative Example 1, in L·m -2 ·h -1 .

[0090] The resolution is:

[0091]

[0092] Wherein, S is the resolution.

[0093] The structural parameters and performance test results of the highly permeable spiral wound ultrafiltration membranes prepared in Examples 1 to 4 and the spiral wound ultrafiltration membranes prepared in Comparative Examples 1 to 4 are shown in Table 1.

[0094] Table 1 Structural parameters and performance test results

[0095]

[0096] As can be seen from the results in Table 1, compared with Comparative Example 1 without adding imidazolium ionic liquid, the permeation performance of Examples 1 to 4 gradually improves, and the permeate fluxes are all higher than 122.8 L·m -2 ·h -1, and when the content of imidazolium ionic liquid is 40 wt.% (Example 3), the permeation flux is the highest, reaching 371.2 L·m -2 ·h -1 , and the promotion rate of the permeation flux is the highest, reaching 202.3%; in addition, the separation performance of Examples 1-4 is also gradually improved compared with that of Comparative Example 1. The Congo red rejection rates of Examples 1-4 are all greater than 98.9%, the separation degrees of Examples 1-4 are all higher than 44.45, and the separation degree of Example 3 is the highest, reaching 93.40. Therefore, on the premise of separation performance, the permeation performance of the membrane is greatly improved. The separation degrees of Comparative Examples 2-4 are all lower than 44.45 of Comparative Example 1, and the permeation flux of Comparative Example 2 decays by 17.75%. The Congo red rejection rates of Comparative Examples 3-4 are reduced to 81.7% and 81.4% respectively, which are not applicable to the high-permeability spiral ultrafiltration membrane system of the present invention.

[0097] In addition, the intermolecular interaction energies between MPD and imidazolium ionic liquid under the conditions of adding different concentrations of imidazolium ionic liquid are calculated respectively:

[0098]

[0099] In the formula, refers to the intermolecular interaction energy between MPD and imidazolium ionic liquid, with the unit of kcal / mol; refers to the total energy of MPD and imidazolium ionic liquid in the system, with the unit of kcal / mol; refers to the energy of MPD in the system, with the unit of kcal / mol; refers to the energy of imidazolium ionic liquid in the system, with the unit of kcal / mol.

[0100] The intermolecular interaction energies between the imidazolium ionic liquid (C6mimCl) molecules and MPD molecules in Example 3 and Comparative Example 2, that is, the intermolecular interaction energies between different concentrations of C6mimCl molecules and MPD molecules are shown in Table 2.

[0101] Table 2 Intermolecular interaction energies between different concentrations of C6mimCl molecules and MPD molecules

[0102]

[0103] According to the molecular simulation data in Table 2, the intermolecular interaction energies between the imidazolium ionic liquid (C6mimCl) and MPD molecules in Comparative Example 2 and Example 3 are -542.08 kcal / mol and -1506.37 kcal / mol respectively, both of which are negative values, that is, the intermolecular π-π interaction forces are attractive, and as the mass concentration of the imidazolium ionic liquid added in the aqueous phase gradually increases, the attractive force between the two increases. Combining Figures 2 to 4From the MSD curves of (Comparative Examples 1, 2 and Example 3), it can be seen that the diffusion rate of the MPD monomer gradually slows down as the concentration of the imidazolium-based ionic liquid increases. In addition, by Figure 1 It can be seen that polyamide structures were successfully formed in Examples 1-4 and Comparative Examples 1-4 without the appearance of new functional groups, and the imidazolium-based ionic liquid did not participate in the IP reaction.

[0104] From Table 1, Figure 5 and Figure 6 From the scanning electron microscope images of the membrane surface, it can be seen that when the mass concentration of the imidazolium-based ionic liquid added is 10 wt.%, the compactness of the leaf-like structure formed on the membrane surface is improved. The volume porosity of the spiral ultrafiltration membrane decreases from 12.31% to 11.72%, the surface porosity decreases from 9.48% to 5.40%, and the average pore size decreases from 9.95 nm to 9.38 nm, resulting in an increase in the rejection rate of Congo red and a decrease in the permeation flux.

[0105] From Table 1, Figures 7 to 10 it can be seen that the leaf-like structure on the membrane surface gradually decreases until it becomes smooth. Compared with Comparative Example 1, the average pore size of Examples 1-4 gradually increases from 9.95 nm to 17.61 nm, and the pore size distribution range decreases. The spiral ultrafiltration membrane with high permeability prepared by the present invention improves the membrane pore uniformity, that is, adding the imidazolium-based ionic liquid improves the membrane permeability and narrows the pore size distribution of the spiral ultrafiltration membrane, while improving the permeation performance and separation performance. This confirms the significant improvement effect of the imidazolium-based ionic liquid on the permeation performance of the spiral ultrafiltration membrane.

[0106] The above results show that the π-π interaction between the imidazolium-based ionic liquid and MPD causes MPD to aggregate under the attraction at low concentrations of the imidazolium-based ionic liquid, react fully with TMC, improve the membrane compactness, reduce the porosity and average pore size, and reduce the permeation flux (Comparative Example 2); conversely, as the concentration of the imidazolium-based ionic liquid increases, the diffusion rate of MPD is slowed down, the dispersion uniformity of MPD is improved, the membrane pore uniformity is improved, the pore size distribution is narrowed, and at the same time, the permeation performance and separation performance of the spiral ultrafiltration membrane are improved (Examples 1-4, Table 1); when the concentration of the imidazolium-based ionic liquid is too high (Comparative Examples 3-4), the diffusion rate of MPD is slowed down too much, the interfacial polymerization reaction cannot proceed normally, and membrane structure blockage and leakage phenomena occur, resulting in a significant reduction in the Congo red rejection rate. Therefore, the optimal concentration range of the imidazolium-based ionic liquid as an aqueous phase additive for the preparation of a spiral ultrafiltration membrane with high permeability is 20-50 wt.%, and the optimal concentration is 40 wt.%.

[0107] Similarly, when the imidazolium-based ionic liquid is 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, or 1-hexyl-3-methylimidazolium bromide, the optimal concentration range for use as an aqueous phase additive in the preparation of high-permeability spiral wound ultrafiltration membranes is also 20-50 wt.%, and the optimal concentration is 40 wt.%.

[0108] In summary, the present invention uses an imidazolium-based ionic liquid as an aqueous phase additive to slow down the diffusion rate of MPD through π-π interaction, regulate the interfacial polymerization reaction, narrow the pore size distribution, and improve the separation performance of small organic molecules / inorganic salts and the permeation performance of the spiral wound ultrafiltration membrane.

[0109] The high-permeability spiral wound ultrafiltration membrane prepared by the present invention can be applied to the treatment of wastewater in fields such as the food industry, pharmaceuticals and biological products, and the printing and dyeing industry, and can be specifically used in processes such as soy sauce / condiment desalination, antibiotic purification, polypeptide / oligonucleotide desalination, and dye / inorganic salt separation.

[0110] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope covered by the present invention.

Claims

1. A preparation method of an ionic liquid-based high-permeability spiral ultrafiltration membrane, characterized in that: It includes the following steps: S1. Pour the aqueous solution containing m-phenylenediamine, ionic liquid, camphorsulfonic acid and triethylamine onto the surface of the polysulfone ultrafiltration membrane. After standing, remove the residual aqueous solution on the surface to obtain Membrane I after treating the polysulfone ultrafiltration membrane with the aqueous solution. The mass fraction of the ionic liquid is 20 - 50 wt.%; the ionic liquid is an imidazolium-based ionic liquid; S2. Pour the organic solution containing trimesoyl chloride onto the surface of Membrane I obtained in Step S1. After standing, remove the residual organic solution on the surface to obtain Membrane II after treating Membrane I with the organic solution; S3. After sequentially draining, heat-treating and rinsing with deionized water the Membrane II obtained in Step S2, a high-permeability spiral ultrafiltration membrane is obtained; The retention rate of the high-permeability spiral ultrafiltration membrane for Congo red reaches 99.0% under the condition of 0.5 MPa, the retention rate of sodium chloride is 1.06%, and the permeation flux reaches 371.2 L m -2 h -1 .

2. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, wherein: The imidazolium-based ionic liquid is one or more of 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium bromide.

3. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In Step S1, the mass fraction of m-phenylenediamine is 0.03 - 0.1 wt.%; the mass fraction of camphorsulfonic acid is 2.5 wt.%; the mass fraction of triethylamine is 1.5 wt.

4. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, wherein: In Step S1, the aqueous solvent in the aqueous solution is deionized water; in Step S2, the organic solvent in the organic solution is n-hexane.

5. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In Step S1, the standing time is 10 - 60 s; in Step S2, the standing time is 30 - 90 s.

6. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In Step S2, the mass fraction of trimesoyl chloride is 0.003 - 0.01 wt.

7. The preparation method of the high-permeability spiral ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In Step S3, after draining Membrane II, place it in a vacuum drying oven. The heat treatment temperature is 60 - 100 °C, and the heat treatment time is 1 - 5 min. Rinse the surface with deionized water multiple times and soak it in deionized water to obtain a high-permeability spiral ultrafiltration membrane.

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