High-permeability spiral-wound ultrafiltration membrane based on ionic liquid and preparation method of high-permeability spiral-wound ultrafiltration membrane

Abstract

The invention relates to a high-permeability roll-type ultrafiltration membrane based on ionic liquid and a preparation method thereof, and belongs to the technical field of roll-type ultrafiltration membrane preparation.The preparation method comprises the steps that firstly, a water-phase solution containing m-phenylenediamine, the ionic liquid, camphorsulfonic acid and triethylamine is poured to the surface of a polysulfone ultrafiltration membrane, after standing is conducted, the residual water-phase solution on the surface is removed, and then the polysulfone ultrafiltration membrane is obtained; treating a polysulfone ultrafiltration membrane with the water-phase solution to obtain a membrane I; pouring an organic solution containing trimesoyl chloride to the surface of the membrane I, standing, and removing the residual organic phase solution on the surface to obtain a membrane II after the membrane I is treated by the organic solution; finally, the membrane II is sequentially subjected to draining, heat treatment and deionized water washing, and the high-permeability roll type ultrafiltration membrane is obtained. The imidazolyl ionic liquid is introduced, the pore size distribution of the roll-type ultrafiltration membrane is narrowed, meanwhile, the permeability and selectivity of the membrane are improved, and the roll-type ultrafiltration membrane is suitable for the fields of food industry, pharmacy and biological product, printing and dyeing textile industry and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of roll-type ultrafiltration membrane preparation, and in particular relates to the preparation of a high-permeability roll-type ultrafiltration membrane based on ionic liquid. Background Art

[0002] Membrane separation technology is widely used in the fields of food industry (soy sauce / condiment desalination), pharmaceuticals (antibiotic purification), biological products (peptide / oligonucleotide desalination), printing and dyeing industry (dye / inorganic salt separation), etc. It has the advantages of high selectivity and low energy consumption in the separation of small molecule organic matter / inorganic salt, but 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 increase the retention rate by changing the pore size or increasing the thickness of the active layer (such as achieving accurate screening of 10-100 kDa molecular weight), it will cause the permeation resistance index to increase, the flux attenuation is as high as 40~60%, and the densified structure is easy to aggravate the concentration polarization, further weakening the effective mass transfer driving force. Therefore, the development of separation membranes with high permeability and high selectivity is a development trend to meet the process requirements of "high-throughput and accurate separation of small molecule organic matter and inorganic salts".

[0003] In order to improve the permeability and separation of separation membranes for small molecular organic matter / inorganic salts in wastewater, commonly used modification methods include selecting new monomers, adding competitive reaction monomers, and porous material-assisted interfacial polymerization (IP) reactions to improve membrane performance. However, the separation membranes prepared by the above methods usually have the following problems: 1) The competition among multiple monomers will inhibit the occurrence of the main reaction, resulting in the formation of a relatively loose or even defective selective layer, which affects the separation effect. 2) Commonly used porous materials are mostly metal organic frameworks (MOFs), which are difficult to crosslink with the membrane to a certain degree of tightness and are easy to fall off, resulting in relatively poor long-term stability of the membrane.

[0004] Rolled ultrafiltration membranes are commonly used for the separation of small molecule organic matter and inorganic salts with a molecular weight greater than 500 Da, for example: separation of dyes / inorganic salts, separation of antibiotics / inorganic salts, separation of soy sauce / inorganic salts, etc. The rolled ultrafiltration membrane is prepared by interfacial polymerization, without introducing new monomers and porous materials, and can maintain a certain stability during long-term operation. However, although the rolled ultrafiltration membrane has the screening performance of small molecule organic matter / inorganic salts, there is still a "seesaw" problem in which permeability and selectivity are difficult to balance. Therefore, it is an important purpose of the present invention to prepare a new type of rolled 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 high-permeability rolled ultrafiltration membrane based on ionic liquids and having improved permeability and separation performance at the same time, and a preparation method thereof.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a high permeability rolled ultrafiltration membrane based on ionic liquid, comprising the following steps:

[0007] S1, pouring an aqueous solution containing m-phenylenediamine, ionic liquid, camphorsulfonic acid and triethylamine onto the surface of the polysulfone ultrafiltration membrane, removing the residual aqueous solution on the surface after standing, and obtaining a membrane I after the polysulfone ultrafiltration membrane is treated with the aqueous solution;

[0008] S2, pouring the organic solution containing trimesoyl chloride onto the surface of the membrane I obtained in step S1, and removing the residual organic phase solution on the surface after standing, to obtain a membrane II after the membrane I is treated with the organic solution;

[0009] S3. The membrane II obtained in step S2 is drained, heat treated and rinsed with deionized water in sequence to obtain a high permeability rolled ultrafiltration membrane.

[0010] Furthermore, in step S1, the ionic liquid is an imidazolyl ionic liquid.

[0011] Furthermore, 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, and 1-hexyl-3-methylimidazolium bromide.

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

[0013] Furthermore, 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.%; and the mass fraction of the ionic liquid is 20-50 wt.%.

[0014] Furthermore, in step S1, the standing time is 10 to 60 s; and in step S2, the standing time is 30 to 90 s.

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

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

[0017] Furthermore, in step S3, after the membrane II is drained, 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 for multiple times, and immersed in deionized water to obtain a high permeability rolled ultrafiltration membrane.

[0018] Another object of the present invention is to provide a method for preparing a high permeability rolled ultrafiltration membrane based on ionic liquid to obtain a high permeability rolled ultrafiltration membrane based on ionic liquid.

[0019] Furthermore, the high permeability spiral ultrafiltration membrane has a Congo red rejection rate of 99.0% and a sodium chloride rejection rate of 1.06% under 0.5 MPa conditions, and a permeate flux of 371.2 L m -2 h -1 .

[0020] Due to the adoption of the above technical scheme, it can be known that the present invention uses imidazolyl ionic liquid as a water phase additive in the interfacial polymerization reaction, and through the π-π mutual attraction between the imidazolyl ionic liquid and meta-phenylenediamine, the diffusion rate of meta-phenylenediamine (MPD) in the interfacial polymerization reaction is slowed down, the uniformity of MPD dispersion is improved, the pore size is optimized, the structural morphology of the aromatic polyamide is adjusted, and a high-permeability rolled ultrafiltration membrane with excellent permeability and separation performance is prepared.

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

[0022] (1) The preparation method is simple and easy to industrialize. As an aqueous phase additive, imidazolyl ionic liquid improves membrane separation performance without participating in the interfacial polymerization reaction. Compared with other modification methods, it is easy to operate and does not require additional production processes and equipment.

[0023] (2) Ionic liquids are less likely to cause damage to the polyamide separation layer and leakage of the bottom membrane - polysulfone ultrafiltration membrane. Compared with conventional modification methods such as selecting new monomers, adding competitive reaction monomers, and using porous materials to assist IP reactions, the advantage of introducing ionic liquids into the aqueous phase is that ionic liquids act from within the IP reaction and do not participate in the IP reaction, effectively avoiding problems such as low cross-linking between the added material and the membrane, easy detachment, and low separation efficiency.

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

[0025] (4) The imidazole ring of the imidazole-based ionic liquid and the benzene ring of MPD can produce π-π interactions, regulate the diffusion rate of aqueous phase monomers, thereby constructing an ionic liquid-MPD film and optimizing the pore size.

[0026] (5) Ionic liquids can change the viscosity of the water phase and adjust the microscopic pore structure of the membrane through the self-assembly effect, thereby enhancing the permeability of the membrane.

[0027] (6) The high permeability rolled ultrafiltration membrane of the present invention can be used for processes such as soy sauce / condiment desalination, antibiotic purification, polypeptide / oligonucleotide desalination, and dye / inorganic salt separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings:

[0029] Figure 1 It is the infrared spectra of the embodiments of the present invention and the comparative examples.

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

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

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

[0033] Figure 5 It is a surface scanning electron microscope image of comparative example 1 of the present invention.

[0034] Figure 6 It is a surface scanning electron microscope image of comparative example 2 of the present invention.

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

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

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

[0038] Figure 10 It is a surface scanning electron microscope image of Example 4 of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the best embodiment.

[0040] In the following examples and comparative examples:

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

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

[0043] Metaphenylenediamine (MPD), analytical grade, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

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

[0045] Triethylamine, analytical grade, was purchased from Tianjin Komiou Co., Ltd.;

[0046] Camphorsulfonic acid was purchased from Shanghai TiCI Chemical Industry Development Co., Ltd.

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

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

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

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

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

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

[0053] Sodium chloride (NaCl), analytical grade, was purchased from China MacLean Biochemical Co., Ltd.

[0054] Embodiment 1:

[0055] A method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid comprises the following steps:

[0056] S1. Take out the polysulfone ultrafiltration membrane from the deionized water, fix it on the homemade organic frame, drain the water droplets on the surface of the polysulfone ultrafiltration membrane, and gently absorb the water droplets on the non-woven fabric on the back. Use the polysulfone ultrafiltration membrane as the base membrane, pour the aqueous solution containing m-phenylenediamine, ionic liquid (1-hexyl-3-methylimidazolium chloride), camphorsulfonic acid and triethylamine onto the surface of the polysulfone ultrafiltration membrane, let it stand for 30 seconds, pour out the excess aqueous solution, and use a rubber rod to roll to remove the residual aqueous solution on the surface to obtain membrane I after the polysulfone ultrafiltration membrane is treated 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.%, and the mass fraction of ionic liquid (1-hexyl-3-methylimidazolium chloride) is 20 wt.%.

[0058] S2. Pour the n-hexane solution containing trimesoyl chloride onto the surface of the membrane I obtained in step S1, let it stand for 60 seconds, and then remove the residual organic phase solution on the surface to obtain membrane II after the membrane I is treated with the organic solution.

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

[0060] S3. Drain the membrane II obtained in step S2 and place it in a vacuum drying oven, heat treat it at 60°C for 3 min, then rinse the surface with deionized water for multiple times and soak it in deionized water to obtain a high permeability rolled ultrafiltration membrane.

[0061] Embodiment 2:

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

[0063] Embodiment 3:

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

[0065] Embodiment 4:

[0066] A method for preparing a high permeability rolled ultrafiltration membrane based on ionic liquid. In step S1, the mass percentage of the 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 an ionic liquid-based highly permeable spiral ultrafiltration membrane. 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 an ionic liquid-based highly permeable spiral ultrafiltration membrane. 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 an ionic liquid-based highly permeable spiral ultrafiltration membrane. 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 an ionic liquid-based highly permeable spiral ultrafiltration membrane. 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 cross-flow filtration device was used to test the separation performance of the highly permeable spiral ultrafiltration membranes prepared in Examples 1-4 and the spiral ultrafiltration membranes prepared in Comparative Examples 1-4.

[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 to test 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 retention rate is:

[0082]

[0083] In the formula, is the salt retention rate, unit is %; C p is the NaCl concentration of the permeate, in mg / L; C f is the NaCl concentration of the feed solution, in mg / L.

[0084] The Congo red retention rate is:

[0085]

[0086] In the formula, is the dye interception rate, unit is %; is the CR concentration of the permeate, in mg / L; is the CR concentration of the feed solution, in mg / L.

[0087] The permeation flux increase rate is:

[0088]

[0089] In the formula, is the permeation flux enhancement rate, unit is %; is the water permeation flux of Examples 1 to 4 or Comparative Examples 2 to 4, in L·m -2 ·h -1 ; is the water permeation flux of comparative example 1, in L·m -2 ·h -1 .

[0090] The separation is:

[0091]

[0092] Where S is the separation degree.

[0093] The structural parameters and performance test results of the high permeability rolled ultrafiltration membranes prepared in Examples 1 to 4 and the rolled 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] From the results in Table 1, it can be seen that compared with the comparative example 1 without adding the imidazolyl ionic liquid, the permeability of Examples 1 to 4 is gradually improved, and the permeation flux is higher than 122.8 L·m -2 ·h -1When the content of imidazolyl ionic liquid was 40 wt.% (Example 3), the permeation flux was the highest, reaching 371.2 L·m -2 ·h -1 , the permeation flux improvement rate is the highest, reaching 202.3%; in addition, the separation performance of Examples 1 to 4 is gradually improved compared with that of Comparative Example 1, and the Congo red retention rates of Examples 1 to 4 are all greater than 98.9%, and the separation degrees of Examples 1 to 4 are all higher than 44.45, and the separation degree of Example 3 is the highest, reaching 93.40. Therefore, under the premise of separation performance, the permeability performance of the membrane is greatly improved. The separation degrees of Comparative Examples 2 to 4 are all lower than 44.45 of Comparative Example 1, and the permeation flux of Comparative Example 2 is attenuated by 17.75%, and the Congo red retention rates of Comparative Examples 3 to 4 are reduced to 81.7% and 81.4%, respectively, which are not suitable for the high permeability spiral ultrafiltration membrane system of the present invention.

[0097] In addition, the intermolecular interaction energy between MPD and imidazolyl ionic liquid was calculated under the conditions of adding different concentrations of imidazolyl ionic liquid:

[0098]

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

[0100] The interaction energy between the imidazolyl ionic liquid (C6mimCl) molecules and the MPD molecules in Example 3 and Comparative Example 2, that is, the interaction energy between the C6mimCl molecules and the MPD molecules at different concentrations is shown in Table 2.

[0101] Table 2 Interaction energy between C6mimCl molecules and MPD molecules at different concentrations

[0102]

[0103] According to the molecular simulation data in Table 2, the intermolecular interaction energy between the imidazolyl ionic liquid (C6mimCl) and MPD in Comparative Example 2 and Example 3 is -542.08 kcal / mol and -1506.37 kcal / mol, respectively, both of which are negative values, that is, there is a mutually attractive π-π interaction force between the molecules, and as the mass concentration of the imidazolyl ionic liquid added to the aqueous phase gradually increases, the mutual attraction between the two increases. 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 with the increase of the concentration of the imidazolyl ionic liquid. Figure 1 It can be seen that Examples 1 to 4 and Comparative Examples 1 to 4 all successfully formed polyamide structures without the appearance of new functional groups, and the imidazole-based ionic liquid did not participate in the IP reaction.

[0104] From Table 1, Figure 5 and Figure 6 From the scanning electron microscopy image of the membrane surface, it can be seen that when the mass concentration of imidazolyl ionic liquid is 10wt.%, the density of the leaf-like structure generated on the membrane surface is improved, the volume porosity of the rolled 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 retention 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 is smooth. Compared with Comparative Example 1, the average pore size of Examples 1 to 4 gradually increases from 9.95 nm to 17.61 nm, and the pore size distribution range decreases. The high permeability wound ultrafiltration membrane prepared by the present invention improves the uniformity of membrane pores, that is, the addition of imidazole-based ionic liquid improves the permeability of the membrane and narrows the pore size distribution of the wound ultrafiltration membrane, while improving the permeability and separation performance. This confirms the significant improvement effect of imidazole-based ionic liquid on the permeability of the wound ultrafiltration membrane.

[0106] The above results show that the π-π mutual attraction between the imidazolyl ionic liquid and MPD makes the MPD aggregated by attraction under low concentration of imidazolyl ionic liquid, fully react with TMC, improve membrane density, reduce porosity and average pore size, and reduce permeation flux (Comparative Example 2); on the contrary, the increase in the concentration of imidazolyl ionic liquid slows down the diffusion rate of MPD, improves the uniformity of MPD dispersion, improves the uniformity of membrane pores, narrows the pore size distribution, and improves the permeability and separation performance of the wound ultrafiltration membrane (Examples 1-4, Table 1); when the concentration of the imidazolyl ionic liquid is too high (Comparative Examples 3-4), the diffusion rate of MPD slows down too much, the interfacial polymerization reaction cannot proceed normally, the membrane structure is blocked and leaked, and the Congo red retention rate is greatly reduced. Therefore, the optimal concentration range of imidazolyl ionic liquid as an aqueous phase additive for the preparation of high permeability wound ultrafiltration membranes is 20-50 wt.%, and the optimal concentration is 40 wt.%.

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

[0108] In summary, the present invention utilizes imidazolyl ionic liquid as an aqueous phase additive to slow down the diffusion rate of MPD through π-π mutual attraction, regulate the interfacial polymerization reaction, narrow the pore size distribution, and improve the small molecule organic / inorganic salt separation performance of the rolled ultrafiltration membrane and the permeability of the membrane.

[0109] The high permeability rolled ultrafiltration membrane prepared by the present invention can be applied to the treatment of wastewater in the fields of food industry, pharmaceutical and biological products, printing and dyeing industry, etc., and can be specifically used for soy sauce / condiment desalination, antibiotic purification, polypeptide / oligonucleotide desalination, dye / inorganic salt separation and the like.

[0110] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit 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 of the present invention.

Claims

1. A method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid, characterized in that: The following steps are involved: S1, pouring an aqueous solution containing m-phenylenediamine, ionic liquid, camphorsulfonic acid and triethylamine onto the surface of the polysulfone ultrafiltration membrane, removing the residual aqueous solution on the surface after standing, and obtaining a membrane I after the polysulfone ultrafiltration membrane is treated with the aqueous solution, wherein the mass fraction of the ionic liquid is 20-50 wt.%; S2, pouring the organic solution containing trimesoyl chloride onto the surface of the membrane I obtained in step S1, and removing the residual organic phase solution on the surface after standing, to obtain a membrane II after the membrane I is treated with the organic solution; S3. The membrane II obtained in step S2 is drained, heat treated and rinsed with deionized water in sequence to obtain a high permeability rolled ultrafiltration membrane.

2. The method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In step S1, the ionic liquid is an imidazolyl ionic liquid.

3. The method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid according to claim 2, characterized in that: The imidazolyl 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, and 1-hexyl-3-methylimidazolium bromide.

4. The method for preparing a high permeability spiral wound 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.%; and the mass fraction of triethylamine is 1.5 wt.%.

5. The method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In step S1, the aqueous phase solvent in the aqueous phase solution is deionized water; in step S2, the organic solvent in the organic solution is n-hexane.

6. The method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In step S1, the standing time is 10 to 60 s; in step S2, the standing time is 30 to 90 s.

7. The method for preparing a high permeability spiral wound 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.%.

8. The method for preparing a high permeability spiral wound ultrafiltration membrane based on ionic liquid according to claim 1, characterized in that: In step S3, after the membrane II is drained, 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 for many times, and immersed in deionized water to obtain a high permeability rolled ultrafiltration membrane.

9. A high permeability spiral wound ultrafiltration membrane, characterized in that; The membrane is prepared by the method for preparing a high permeability rolled ultrafiltration membrane based on ionic liquid according to any one of claims 1 to 8.

10. The high permeability spiral wound ultrafiltration membrane according to claim 9, characterized in that: At 0.5 MPa, the retention rate of Congo red was 99.0%, the retention rate of sodium chloride was 1.06%, and the permeate flux was 371.2 L m -2 h -1 .

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