Crown ether functionalized mixed matrix membrane based on hydrogen bond crosslinking for lithium isotope separation as well as preparation method and application of crown ether functionalized mixed matrix membrane

Abstract

The invention belongs to the technical field of isotope separation, and particularly relates to a crown ether functionalized mixed matrix membrane based on hydrogen bond crosslinking for lithium isotope separation and a preparation method and application thereof. The crown ether functionalized mixed matrix membrane is prepared from a polymer with one of the following structures, and m and n are polymerization degrees. The crown ether functionalized mixed matrix membrane provided by the invention has 12C4, 14C4 or 15C5 crown ether groups which specifically act with 6Li, and in addition, hydroxyl in the structure and the crown ether groups form a hydrogen bond network, so that crown ether is pre-organized into a more continuous structure, charge compensation for migration of part of Li ions among crown ether is provided, and a desorption energy barrier is reduced. An electrodialysis diffusion system or a static diffusion system constructed based on the crown ether functionalized mixed matrix membrane can realize separation of < 6 > Li < + > and < 7 > Li < + >, and the whole separation process is simple to operate, environment-friendly and efficient.

Description

Technical Field

[0001] This invention belongs to the field of isotope separation technology, specifically relating to a crown ether-functionalized mixed matrix membrane based on hydrogen bond crosslinking for lithium isotope separation, its preparation method, and its application. Background Technology

[0002] Lithium (Li) is known as the "energy metal of the 21st century". It is mainly found in solid lithium ore and lithium-rich natural water. my country's lithium reserves are as high as 15.184 million tons, of which nearly half of the lithium resources are stored in the form of salt lake brine in Qinghai Province.

[0003] Lithium exists in nature 6 Li and 7 Li has two stable isotopes, among which 6 The Li abundance was 7.53%. 6 Li has a strong neutron-trapping ability and can produce tritium, an important raw material for nuclear fusion, during neutron bombardment, releasing a large amount of energy, making it an ideal nuclear fuel for nuclear reactors. It is estimated that 1 kg of tritium... 6 Li, through nuclear fusion, produces more energy than burning 20,000 tons of high-quality coal, and far more than the energy produced by the same mass of coal. 235 The energy released during U fission. However 6 Li must have an abundance of 30% or more to be used as a tritium additive.

[0004] 7 Li has a small neutron absorption cross section, and when its abundance is above 99.92%, it can be used as a pH adjuster in pressurized water reactors; when its abundance is above 99.995%, it can be used as a coolant in thorium molten salt reactors. Therefore, 6 Li and 7 The separation of Li is of great significance for the development and application of the future nuclear fusion industry.

[0005] Currently, the only lithium isotope separation method used in industrial production is the lithium amalgam method. However, the use of large amounts of metallic mercury poses certain risks to human health and the environment. Methods currently under development and research mainly fall into two categories: electro-driven separation methods utilizing the difference in intrinsic ionic mobility between two ions, and separation methods utilizing functional materials with different interactions. The former includes electromigration, electrodeposition, electrodialysis, and electrointercalation, while the latter mainly includes chemical precipitation, adsorption separation, solvent extraction, and membrane separation. Adsorption methods often suffer from poor permeability, high cost, and difficulties in granulation. Extraction methods are prone to emulsification during extraction, and chemical precipitation methods have complex processes. In comparison, membrane separation is more environmentally friendly and can be integrated with other testing systems to further improve performance, showing significant development potential.

[0006] Improving the stability of membrane structures and developing membrane materials with good separation factors are issues that need to be addressed. Summary of the Invention

[0007] To address the technical problems existing in the prior art, the first objective of this invention is to provide a crown ether-functionalized hybrid matrix membrane based on hydrogen bond crosslinking for lithium isotope separation.

[0008] A second objective of this invention is to provide a method for preparing the crown ether functionalized mixed matrix membrane as described above.

[0009] A third objective of this invention is to provide a method for separating crown ether-functionalized hybrid matrix membranes as described above. 6 Li + and 7 Li + Applications in [the context of the text].

[0010] The fourth object of the present invention is to provide a method for separating 6 Li + and 7 Li + A static diffusion system.

[0011] The fifth object of the present invention is to provide a method for separating 6 Li + and 7 Li + Electrodialysis diffusion system.

[0012] To achieve the first objective mentioned above, the present invention adopts the following technical solution: This invention discloses a crown ether-functionalized hybrid matrix membrane based on hydrogen bond crosslinking for lithium isotope separation, wherein the crown ether-functionalized hybrid matrix membrane is prepared using a polymer with one of the following structures; I; II; III; Where m and n are the degrees of polymerization, m is 95-99% and n is 78-85%.

[0013] In the above polymers, the structure contains [the following]. 6 The specific action of 12C4, 14C4, or 15C5 crown ether groups on Li facilitates the achievement of [the desired effect]. 6 The Li-specific ion selection, in addition to the hydrogen bond network formed by the hydroxyl groups in the structure and the crown ether groups, allows the crown ether to "pre-organize" into a more continuous structure, and provides some charge compensation for the migration of Li ions between the crown ether groups, reducing the desorption energy barrier and making the film continuous.

[0014] Furthermore, the crown ether functionalized mixed matrix membrane has a crown ether grafting rate of 30-50%.

[0015] To achieve the second objective mentioned above, the present invention adopts the following technical solution: This invention discloses a method for preparing the crown ether functionalized mixed matrix membrane as described above, comprising the following steps: S1. Under alkaline conditions, bis(4-fluorophenyl) sulfone and 2-methoxyhydroquinone undergo a nucleophilic substitution polycondensation reaction to obtain the polymer shown in formula A-1 below, where p is the degree of polymerization and p is 78-85%; A-1; S2. The polymer obtained in step S1 is demethylated to obtain the first polymer shown in formula A; A; S3. Under an inert atmosphere, using 2-(hydroxymethyl)-12-crown 4, 2-(hydroxymethyl)-14-crown 4 or 2-(hydroxymethyl)-15-crown 5 as raw materials, and reacting with p-toluenesulfonyl chloride, the functional monomers shown below are obtained. ; Where R is selected from , or ; S4. Under an inert atmosphere, the functional monomer obtained in step S3 is mixed with the first polymer obtained in step S2 and dehydrogenated to obtain the second polymer as shown in formula B below. B; S5. The first polymer obtained in step S2 and the second polymer obtained in step S4 are mixed in proportion and dissolved in an organic solvent. After the solvent has completely evaporated, the matrix membrane is obtained.

[0016] Furthermore, the molar ratio of bis(4-fluorophenyl) sulfone to 2-methoxyhydroquinone is 1:1-1.1.

[0017] Furthermore, the nucleophilic substitution condensation reaction is first carried out at 120-140℃ for 4-8 hours, and then the temperature is raised to 140-160℃ for another 4-8 hours.

[0018] Furthermore, the alkaline environment in step S1 is achieved by adding inorganic salts such as potassium carbonate, sodium carbonate, potassium hydroxide, or sodium hydroxide.

[0019] Furthermore, the molar ratio of 2-(hydroxymethyl)-12-crown 4, 2-(hydroxymethyl)-14-crown 4, or 2-(hydroxymethyl)-15-crown 5 to p-toluenesulfonyl chloride is 1:1.05-1.1.

[0020] Furthermore, the molar ratio of the functionalized monomer to the first polymer is 1.1-1.2:1.

[0021] Furthermore, the reaction temperature in step S4 is 140-160℃, and the reaction time is 6-8h.

[0022] Furthermore, the mass ratio of the first polymer to the second polymer is 1:1 to 2:1.

[0023] Furthermore, the total mass concentration of the first polymer and the second polymer in the organic solvent is 3-5%, and the solvent evaporation temperature is 60-120℃.

[0024] To achieve the third objective mentioned above, the present invention adopts the following technical solution: This invention discloses a method for using crown ether-functionalized hybrid matrix membranes as described above in the separation process. 6 Li + and 7 Li + Applications in [the context of the text].

[0025] To achieve the fourth objective mentioned above, the present invention adopts the following technical solution: This invention discloses a method for separating 6 Li + and 7 Li + A static diffusion system, comprising a diffusion chamber, a separation membrane, and a receiving chamber arranged sequentially; the static diffusion system is supplied with... 6 Li + and 7 Li + The solution; The separation membrane is, as described above, a crown ether functionalized mixed matrix membrane.

[0026] Furthermore, the aforementioned 6 Li + and 7 Li + The solution is selected from one or more of lithium nitrate solution, lithium chloride solution, lithium bromide solution, lithium iodide solution, lithium carbonate solution, lithium sulfate solution, and lithium chlorate solution.

[0027] To achieve the fifth objective mentioned above, the present invention adopts the following technical solution: This invention discloses a method for separating 6 Li + and 7 Li + An electrodialysis diffusion system, comprising an anode, a diffusion chamber, a separation membrane, a receiving chamber, and a cathode; the electrodialysis diffusion system also supplies... 6 Li+ and 7 Li + Electrolyte solution; The separation membrane is, as described above, a crown ether functionalized mixed matrix membrane.

[0028] Furthermore, the electrolyte solution is selected from one or more of lithium nitrate solution, lithium chloride solution, lithium bromide solution, lithium iodide solution, lithium carbonate solution, lithium sulfate solution, and lithium chlorate solution.

[0029] Furthermore, the electrodialysis diffusion system also includes a power source, the two poles of which are connected to the cathode and anode respectively to supply power to the system.

[0030] The beneficial effects of this invention are as follows: The crown ether-functionalized hybrid matrix membrane based on hydrogen bonding crosslinking described in this invention is prepared using a polymer with one of the structures of formulas I to III. This polymer uses crown ether groups as the core functional groups, fully utilizing their... 6 Li + and 7 Li + The ion selection process during separation, and the introduction of hydroxyl groups as hydrogen bond donors to interact with crown ether acceptors, helps shorten the effective distance between adjacent crown ethers and provides a hydrogen-bonded hopping path for lithium ion migration. This synergistic effect lowers the activation energy for lithium ion migration between crown ether sites, further expanding the range of crown ether acceptors. 6 Li + and 7 Li + The ion-selective effect of the crown ether allows for better separation. The entire preparation process is conducted under mild reaction conditions, resulting in a uniform crown ether-functionalized mixed matrix membrane with excellent mechanical properties. Furthermore, most reported preparation methods involve post-modification of the polymer substrate to introduce crown ethers. This often results in uneven distribution of functional groups, a tendency for gradient distribution, low modification efficiency, incomplete reactions, and difficulty in performing complex multi-step modifications. In contrast, this invention allows for convenient adjustment of the crown ether addition amount to achieve 0-100% crown ether grafting according to actual application needs, thereby saving production costs.

[0031] Building upon this, the present invention further combines crown ether-functionalized mixed matrix membranes with static diffusion and electrodialysis membrane separation processes for lithium isotope separation, based on the crown ether group pair. 6 Li + and 7 Li + The ion-selective effect of the ion can be fully utilized. 6 Li + and 7 Li +The difference in mobility enables the separation of lithium isotopes, while the hydrogen bonds in the structure provide assistance for lithium-ion migration. In one specific embodiment, 6 Li + and 7 Li + The single-stage selectivity is 1.0712, and the separation process is continuous, stable, energy-efficient, and highly effective. Attached Figure Description

[0032] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0033] Figure 1 An electron micrograph of the crown ether functionalized mixed matrix membrane prepared in Example 1 is shown.

[0034] Figure 2 The contact angle diagram of the crown ether functionalized mixed matrix membrane prepared in Example 1 is shown.

[0035] Figure 3 The NMR spectrum of the polymer of formula 2 prepared in Example 1 is shown.

[0036] Figure 4 The NMR spectrum of the polymer of formula 4 prepared in Example 1 is shown.

[0037] Figure 5 The infrared spectrum of the crown ether functionalized mixed matrix membrane prepared in Example 1 is shown, wherein, Figure 5 The left image shows the complete infrared spectrum, and the right image shows the spectrum at 900-1000 cm⁻¹. -1 A magnified view of a portion of the area.

[0038] Figure 6 A schematic diagram of the apparatus used in the static diffusion test in Test Example 1 is shown.

[0039] Figure 7 A schematic diagram of the apparatus used for the electrodialysis diffusion test in Test Example 2 is shown. Detailed Implementation

[0040] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0041] In this invention, the preparation methods are all conventional unless otherwise specified, and the raw materials used can be obtained from publicly available commercial sources or prepared according to existing technology unless otherwise specified.

[0042] Example 1 50%-12C4@PES Where m and n are the degrees of polymerization, m is 95-99% and n is 78-85%.

[0043] This embodiment provides a method for preparing a crown ether-functionalized hybrid matrix membrane based on hydrogen bond crosslinking. The membrane is prepared using a polymer 50%-12C4@PES with the structure shown above. The synthetic route of this polymer is illustrated below:

[0044] Weigh 2.5 g of bis(4-fluorophenyl) sulfone, 1.4 g of 2-methoxyhydroquinone, and 4.0 g of potassium carbonate into a 100 mL round-bottom flask, add 40 mL of DMSO to dissolve them, heat to 120 °C and react for 6 h, then further heat to 140 °C and react for 6 h, cool to room temperature, filter the polymer, wash 2-3 times with DMSO and water, and vacuum dry in a vacuum oven to obtain the polymer shown in Formula 1.

[0045] Weigh 4 g of the polymer shown in Formula 1 into a 250 mL round-bottom flask, add 100 mL of dichloromethane to dissolve it, add 2 mL of boron tribromide at 0 °C, react for 8 h, wash with water and extrude, and vacuum dry in a vacuum oven to obtain the polymer shown in Formula 2.

[0046] Weigh 2.0 g of 2-(hydroxymethyl)-12-crown4 into a 100 mL round-bottom flask. Place the system under nitrogen protection and add anhydrous dichloromethane through a syringe. Stir to dissolve. Slowly add 4 mL of anhydrous triethylamine through a syringe. Add 2.0 g of p-toluenesulfonyl chloride dissolved in a small amount of anhydrous dichloromethane in batches. Stir at low temperature for 1 h and at room temperature for 6-8 h to obtain the functional molecule shown in Formula 3.

[0047] Weigh 3.0 g of the polymer shown in Formula 2 into a 100 mL round-bottom flask, ensuring the entire system is under nitrogen protection. Then, add an appropriate amount of DMSO to completely dissolve the polymer. Add 0.3 g of sodium hydride in batches at low temperature and stir for 0.5-1 h. Then, add a DMSO solution containing 3.0 g of the functional molecule shown in Formula 3 and heat at 140 °C for 6 h. Cool to room temperature, add methanol and water to quench the reaction, extract the organic phase with dichloromethane, wash with saturated brine, dry with anhydrous sodium sulfate, filter, and concentrate under reduced pressure using a rotary evaporator to remove the solvent, obtaining the polymer shown in Formula 4.

[0048] Weigh 25 mg of the polymer shown in Formula 2 and 25 mg of the polymer shown in Formula 4, dissolve them in 1 mL of DMSO, stir and dissolve evenly at 80 °C and let stand for 6-8 h, then transfer to a glass petri dish, wait for the solvent to evaporate to dryness at 80 °C to obtain the crown ether functionalized mixed matrix membrane with a thickness of 10 μm.

[0049] Scanning electron microscopy (SEM) testing: The prepared crown ether functionalized mixed matrix membrane was dried in an oven. A flat membrane sample was then attached to the sample stage surface for SEM testing. The results are shown below. Figure 1 As shown, from Figure 1 It can be seen that a uniform and dense membrane material was prepared.

[0050] Contact angle test: The prepared crown ether functionalized mixed matrix membrane was dried in an oven, and a flat membrane sample was taken for static contact angle measurement. Measurement was performed at room temperature using deionized water via the hanging drop method; a water droplet was placed on the membrane surface in the air using a microsyringe, and after standing for 5 seconds, the image of the water droplet was recorded. The water contact angle was measured from the recorded image, and the results are shown below. Figure 2 As shown, its water contact angle is 72.48°, indicating that the crown ether functionalized mixed matrix membrane is relatively hydrophilic.

[0051] NMR testing: Take 5 mg of the polymers shown in Formula 2 and Formula 4 into NMR tubes, add 600 μL of D-DMSO to completely dissolve them into a homogeneous and stable solution, and perform NMR at 600 Hz. 1 H NMR test, results as follows Figure 3 , Figure 4 As shown, the target molecule was successfully synthesized.

[0052] Fourier Transform Infrared (FTIR) Measurement: The prepared crown ether-functionalized mixed matrix membrane was dried in an oven at 60 ℃, and a flat membrane sample was used for FTIR measurement. Subsequently, the membrane was dried again in an oven at 110 ℃, and a flat membrane sample was used for FTIR measurement. Results are as follows: Figure 5 As shown in the figure, heating to above the boiling point of water ensures the absence of water molecules in the system, and the infrared characteristic peaks show a significant shift, proving the existence of a hydrogen bond network.

[0053] Test Example 1: Static Diffusion Performance Test The crown ether functionalized hybrid matrix membrane prepared in Example 1 was subjected to... 6 Li + / 7 Li + The specific steps for static diffusion performance testing are as follows: The crown ether functionalized mixed matrix membrane to be tested was dried and placed in a permeation device (e.g., Figure 6 As shown, the permeation device includes a diffusion chamber, a separation membrane (composed of the crown ether functionalized mixed matrix membrane to be tested), and a receiving chamber. A 0.1 mol / L lithium nitrate solution is added to the diffusion chamber, and an equal volume of water is added to the receiving chamber. The solution in the receiving chamber is detected by inductively coupled plasma mass spectrometry (ICP-MS). The crown ether functionalized mixed matrix membrane... 6 Li + / 7 Li+ The static diffusion selectivity can reach up to 1.0712.

[0054] Test Example 2: Electrodialysis Performance Test The crown ether functionalized hybrid matrix membrane prepared in Example 1 was subjected to... 6 Li + / 7 Li + The specific steps for electrodialysis performance testing are as follows: The crown ether functionalized mixed matrix membrane to be tested was dried and placed in a permeation device (e.g., Figure 7 As shown, the permeation device includes a diffusion chamber, a separation membrane (composed of the crown ether functionalized mixed matrix membrane to be tested), and a receiving chamber. A 0.1 mol / L lithium nitrate solution is added to the diffusion chamber, and an equal volume of water is added to the receiving chamber. A platinum rod with a diameter of 1 mm and a length of 5 cm is inserted at the same position in the permeation chamber and the receiving chamber. The platinum rod is inserted 1 mm below the liquid surface. The platinum rod in the permeation chamber is connected to the positive terminal of the power supply, and the platinum rod in the receiving chamber is connected to the negative terminal of the power supply.

[0055] Electrodialysis was performed in constant voltage mode, with an operating voltage of 0.01-0.05V. The solution in the receiving chamber was detected by inductively coupled plasma mass spectrometry (ICP-MS). At an applied voltage of 0.01V, the crown ether-functionalized mixed matrix membrane... 6 Li + / 7 Li + The static diffusion selectivity was 1.0402, and the crown ether functionalized mixed matrix membrane exhibited high selectivity at an applied voltage of 0.05 V. 6 Li + / 7 Li + The static diffusion selectivity was 1.0213. Under all test conditions, the crown ether functionalized mixed matrix membrane exhibited [specific characteristics / performance]. 6 Li + / 7 Li + The diffusion selectivity of electrodialysis can reach up to 1.0402.

[0056] Example 2 30%-12C4@PES Where m and n are the degrees of polymerization, m is 95-99% and n is 78-85%.

[0057] The preparation of polymer 30%-12C4@PES follows the same synthetic route as in Example 1, except for the final preparation step: Weigh 35 mg of the polymer shown in Formula 2 and 15 mg of the polymer shown in Formula 4, dissolve them in 1 mL of DMSO, stir at 80°C until homogeneous, and let stand for 6-8 h. Then transfer to a glass petri dish and allow the solvent to evaporate to dryness at 80°C to obtain the crown ether functionalized mixed matrix membrane with a thickness of 10 μm. It should be noted that because the ratio of the polymers shown in Formula 2 and Formula 4 is different from that in Example 1, the structure of the polymer 30%-12C4@PES obtained under hydrogen bonding is different.

[0058] Test Example 3 The crown ether functionalized hybrid matrix membrane prepared in Example 2 was subjected to... 6 Li + / 7 Li + Static diffusion performance testing was conducted using the same procedure as in Test Example 1 and Example 2, on the crown ether functionalized mixed matrix membrane prepared in Example 2. 6 Li + / 7 Li + The static diffusion selectivity is 1.0650.

[0059] Comparative Example 1 Weigh 50 mg of the polymer shown in Formula 2, dissolve it in 1 mL of DMSO, stir and dissolve it evenly at 80 °C and let it stand for 6-8 h, then transfer it to a glass petri dish and let the solvent evaporate to dryness at 80 °C to obtain the membrane material with a thickness of 10 μm.

[0060] The membrane material prepared in Comparative Example 1 was subjected to... 6 Li + / 7 Li + Static diffusion performance test, the test procedure is the same as in Test Example 1. 6 Li + / 7 Li + The static diffusion selectivity is 1.01.

[0061] Fourier Transform Infrared (FTIR) Measurement: The crown ether-functionalized mixed matrix membrane prepared in Comparative Example 1 was dried in an oven at 60 ℃, and a flat membrane sample was taken for FTIR measurement. Subsequently, the membrane was dried again in an oven at 110 ℃, and a flat membrane sample was taken for FTIR measurement. The results are shown in the figure. Figure 5 As can be seen from the data, heating the system above the boiling point of water ensures that no water molecules are present in the system, and the infrared characteristic peaks do not show a significant shift, proving that the hydrogen bond network is very weak.

[0062] As can be seen from the above embodiments, the membrane fabrication process of the crown ether-functionalized mixed matrix membrane based on hydrogen bond crosslinking prepared in this invention is simple, controllable, and efficient. Based on this, this invention combines this crown ether-functionalized mixed matrix membrane based on hydrogen bond crosslinking with a static diffusion system and an electrodialysis membrane separation system for lithium isotope separation. 6 Li + , 7 Li + The bonding forces are different, and under the driving action of an external electric field, 6 Li + Electromobility greater than 7 Li + The two work synergistically to achieve the separation of lithium isotopes. In an embodiment of the invention, 6 Li + / 7 Li + The selected method for lithium isotope separation has excellent separation performance and is safe, environmentally friendly, and features a continuous, stable, energy-efficient, and energy-saving separation process.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A hydrogen-bond cross-linked based crown ether functionalized mixed matrix membrane for lithium isotope separation, characterized in that, The crown ether functionalized mixed matrix membrane is prepared by using a polymer with one of the following structures: I； II; III; Wherein, m, n are the polymerization degree, m is 95-99%, and n is 78-85%.

2. The crown ether functionalized mixed matrix membrane according to claim 1, wherein, The crown ether grafting rate of the crown ether functionalized mixed matrix membrane is 30-50%.

3. The method for preparing a crown ether functionalized mixed matrix membrane according to claim 1 or 2, characterized in that, The method comprises the following steps: S1. Under alkaline conditions, nucleophilic substitution polycondensation reaction of bis(4-fluorophenyl) sulfone and 2-methoxy hydroquinone is carried out to obtain a polymer shown in formula A-1, and p is the polymerization degree, p is 78-85%; A-1； S2. The polymer obtained in step S1 is subjected to demethylation to obtain a first polymer shown in formula A; A； S3. Under an inert atmosphere, 2-(hydroxymethyl)-12-crown-4, 2-(hydroxymethyl)-14-crown-4 or 2-(hydroxymethyl)-15-crown-5 is used as a raw material, and p-toluenesulfonyl chloride is reacted to obtain a functional monomer shown in the following formula; ； wherein R is selected from , or ; S4. Under an inert atmosphere, the functional monomer obtained in step S3 is mixed with the first polymer obtained in step S2 to obtain a second polymer shown in formula B through dehydrogenation; B； S5. The first polymer obtained in step S2 and the second polymer obtained in step S4 are mixed in proportion, dissolved in an organic solvent, and the solvent is completely volatilized to obtain the matrix membrane.

4. The production method according to claim 3, characterized by, The molar ratio of bis(4-fluorophenyl) sulfone to 2-methoxy hydroquinone is 1:1-1.1; The nucleophilic substitution polycondensation reaction is first reacted at 120-140℃ for 4-8h, and then heated to 140-160℃ for 4-8h.

5. The production method according to claim 3, characterized by, The molar ratio of 2-(hydroxymethyl)-12-crown-4, 2-(hydroxymethyl)-14-crown-4 or 2-(hydroxymethyl)-15-crown-5 to p-toluenesulfonyl chloride is 1:1.05-1.

1.

6. The production method according to claim 3, characterized by, The molar ratio of the functional monomer to the first polymer is 1.1-1.2:1; The reaction temperature of step S4 is 140-160℃, and the reaction time is 6-8h.

7. The production method according to claim 3, characterized by, The mass ratio of the first polymer to the second polymer is 1:1 to 2:1; The total mass concentration of the first polymer and the second polymer in the organic solvent is 3-5%, and the volatilization temperature of the solvent is 60-120℃.

8. Use of the crown ether functionalized mixed matrix membranes according to claim 1 or 2 for the separation of 6 Li + and 7 Li + .

9. A static diffusion system for separating 6 Li + and 7 Li + characterized in that, The static diffusion system comprises a diffusion chamber, a separation membrane and a receiving chamber arranged in sequence; the static diffusion system is supplied with 6 Li + and 7 Li + solution; The separation membrane is the crown ether functionalized mixed matrix membrane according to claim 1 or 2.

10. An electrodialytic diffusion system for separating 6 Li + and 7 Li + characterized in that The electrodialytic diffusion system is provided with an anode, a diffusion chamber, a separation membrane, a receiving chamber and a cathode; the electrodialytic diffusion system is also supplied with 6 Li + and 7 Li + electrolyte solution; The separation membrane is the crown ether functionalized mixed matrix membrane according to claim 1 or 2.

Images