A polyelectrolyte material, a method for preparing the same and a cation-selective separation membrane

Abstract

This invention relates to the field of cation-selective separation membranes, specifically a polyelectrolyte material, its preparation method, and a cation-selective separation membrane. The invention provides a polyelectrolyte material, its preparation method, and a cation-selective separation membrane. By designing the structure of the polyelectrolyte, the microstructure of the constructed membrane can be controlled. Utilizing the self-assembly properties of molecules, ion-selective transport channels containing both crown ether groups and sulfonic acid groups are constructed. The polyelectrolyte material provided by this invention exhibits high cation separation performance when applied to cation-selective separation membranes. The preparation method is simple and can be mass-produced industrially. Experiments show that the selective permeability P of the cation-selective separation membrane made from the polyelectrolyte material provided by this invention is high. (K+ / Mg2+) It reached 90.3; P (H+ / Fe2+) It reached 3153.

Description

Technical Field

[0001] This invention relates to the field of cation selective separation membranes, specifically a polyelectrolyte material, its preparation method, and a cation selective separation membrane. Background Technology

[0002] Ion selective separation, as an important application area of ​​membrane separation technology, involves energy conversion and storage, environmental pollution and detection, clean industrial production, and resource recycling, and represents a cutting-edge scientific issue in the field of membrane separation. For example, the selective separation of hydrogen ions and metal ions in acidic wastewater involves environmental protection, resource recycling, and energy conservation, emission reduction, and consumption reduction across society. These acidic wastewaters contain H2SO4, HNO3, HCl, HCN, H3PO4, or mixtures thereof, posing a significant threat to the environment. Typically, each ton of steel produced generates approximately 55–75 kg of pickling wastewater, in addition to 20–50 times that amount of pickling wastewater. Furthermore, selective ion separation is also involved in applications such as lithium extraction from high magnesium-to-lithium ratio brine, the separation of sodium and calcium ions during brine refining in the chlor-alkali industry, and the separation of chloride and sulfate ions in high-salinity wastewater treatment.

[0003] Selective electrodialysis (SEM), a membrane separation technology driven by potential difference, has been widely applied in the aforementioned fields due to its advantages such as low energy consumption, simple operation, and environmental friendliness. The ion-selective separation membrane, as the core component of the SEM process, directly determines the recovery efficiency of ion selective separation throughout the process. However, currently commercially available ion-selective separation membranes often suffer from low ion selectivity, complex manufacturing processes, and high operating costs. Therefore, developing highly selective ion-selective separation membranes is an urgent problem that needs to be overcome to further expand the application of SEM in the field of ion separation.

[0004] Current research on the preparation of ion-selective separation membranes mainly focuses on the surface modification of commercial ion exchange membranes. For example, surface coating, interfacial polymerization, and surface deposition are used to modify the surface functional layer, alter the membrane surface charge, and change the surface density. The Elsevier journal *Journal of Membrane Science*, 553, 2018, 139-150, reported a method for constructing a polydopamine and polyethyleneimine composite layer on the surface of a sulfonated polyethersulfone cation exchange membrane via surface co-deposition, achieving H… + / Zn 2+The selectivity is approximately 10. This modification method involves complex preparation steps, poor process controllability, and is unsuitable for continuous production, and its selectivity is relatively low. Elsevier's Journal of Membrane Science, 595, 2020, 117544, reported the construction of a polyaniline separation layer on the surface of a sulfonated polyphenylene sulfone cation exchange membrane via surface polymerization, and the construction of a cation-selective separation membrane by quaternization modification of the polyaniline layer. However, this modification method is not suitable for large-area preparation, as the preparation steps are complex and the process controllability is poor. Furthermore, its Na... + / Mg 2+ Selectivity (4.1) and Li + / Mg 2+ The selectivity (1.75) is not high, mainly because its ion-selective separation is primarily based on the electrostatic repulsion of the positively charged polyaniline layer on the surface, without forming a selective transport channel for monovalent cations. Elsevier's Journal of Membrane Science, 594, 2020, 117453, reported a method for constructing a polyamide separation layer on a porous polyacrylonitrile substrate via interfacial polymerization, and achieving cation-selective separation membrane construction through quaternization modification of the polyamide separation layer. + / Mg 2+ Selectivity can reach 11.3. However, this construction method also suffers from complex preparation steps. Moreover, while porous polyacrylonitrile substrates reduce ion transport resistance within them, they also suffer from high common ion leakage rates, i.e., low migration numbers.

[0005] Based on relevant data, it can be seen that cation selective separation membranes currently face problems such as complex production processes, ion selectivity depending on surface modification layers, low separation efficiency, lack of specificity for specific ions, and weak adhesion between the modified layer and the base membrane. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a polyelectrolyte material, a preparation method thereof, and a cation selective separation membrane. The polyelectrolyte material provided by the present invention can be applied to cation selective separation membranes, has high cation separation performance, and the preparation method is simple and can be mass-produced industrially.

[0007] This invention provides a polyelectrolyte material with the structure shown in formula (A):

[0008]

[0009] Where x = 0.01 to 0.99, and n represents the degree of aggregation;

[0010] Ab is a group with the structure shown in formula (α) or formula (β); in formula (α), Af is C6 to C6. 22 The aryl group; m and n are independently integers from 1 to 5; in formula (β), Aa is C6 to C6. 22 The aryl group; z and q are independent integers from 1 to 5;

[0011]

[0012] Crown ether is a group with the structure shown in formula (β); in formula (β), x and y are independently integers from 1 to 5;

[0013]

[0014] Aj is a group with the structure shown in formula (δ); in formula (δ), R1 and R2 are independently selected from any one of hydrogen, halogen, substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C1-C5 alkyl ester, substituted or unsubstituted phenyl.

[0015]

[0016] The Ab described in this invention is one or more of a biphenyl compound containing a sulfonic acid group or a substituent formed from a compound containing a biphenyl structure. By introducing side-chain sulfonic acid groups through the polymerization of biphenyl compounds containing sulfonic acid groups or monomers containing biphenyl structures, a hydrophilic-hydrophobic microphase separation structure is achieved, thereby enabling rapid ion transport. Specifically, strongly polar sulfonic acid groups aggregate to form ion clusters. In an aqueous environment, these ion clusters hydrate and swell, forming continuous hydrophilic ion channels. The sulfonic acid groups act as the main ion exchange sites in the membrane matrix, promoting efficient ion transport.

[0017] In some embodiments of the present invention, the Ab is a group with the structure shown in formula (α); in formula (α), the Af is C6 to C6. 22 The aryl group is preferably phenyl, naphthyl, or anthracene; m and n are independently integers from 1 to 5, preferably integers from 1 to 3.

[0018]

[0019] In some embodiments of the present invention, the Ab is a group with the structure shown in formula (β); in formula (β), the Aa is C6 to C6. 22 The aryl group is preferably phenyl, naphthyl, or anthracene; z and q are independently integers from 1 to 5, preferably integers from 1 to 3.

[0020]

[0021] In one embodiment, the structure of Ab is shown in any of equations (a) to (e):

[0022]

[0023] The crown ether described in this invention is one or more substituents formed from dibenzocrown ether compounds. The polyelectrolyte material of this invention adjusts the hydrophilicity / hydrophobicity of the membrane and introduces new ion exchange sites by controlling the ratio of the dibenzocrown ether monomer to the sulfonic acid-containing biphenyl (or biphenyl-containing structure) monomer, i.e., the ratio of the crown ether to the Ab. Specifically, the dibenzocrown ether monomer is uncharged, the oxygen-containing macrocycle has a hydrophilic porous structure, the benzene ring is hydrophobic, and the dibenzocrown ether monomer is an amphiphilic molecule. The oxygen-containing macrocycle has host-guest interactions with hydrated hydrogen ions or alkali metal ions. Replacing some sulfonic acid units with crown ether units as crown-shaped recognition sites can improve the selectivity for specific ions. Simultaneously, the crown ether forms a positively charged complex with specific ions and generates electrostatic interactions with the negatively charged sulfonic acid groups, forming a synergistic ion transport network. The novel synergistic hydrophilic network formed by the crown ether and sulfonic acid groups improves the chain stability of the polymer membrane. This novel synergistic hydrophilic transport system achieves highly efficient and selective transport of specific ions when the molar ratio of the sulfonic acid-substituted aryl monomer compound and the dibenzocrown ether monomer compound is preferably 1:4.

[0024] In some embodiments of the present invention, the Crown ether is a group with the structure shown in formula (β); in formula (β), x and y are independently integers from 1 to 5;

[0025]

[0026] In one embodiment, the structure of the Crown ether is shown in any of equations (g) to (n):

[0027]

[0028] In this invention, Aj represents one or more substituents formed from carbonyl compounds. This invention utilizes carbonyl compounds in polymerization to introduce different connecting units into the polyelectrolyte material and to regulate the microstructure of the membrane. Specifically, based on the different connecting units, the polyelectrolyte material promotes molecular self-assembly behavior during the construction of a cation-selective separation membrane. The main carbon chain tends to aggregate into hydrophobic regions, while hydrophilic structural units containing crown ether groups and sulfonic acid groups tend to aggregate into hydrophilic regions, i.e., ion-selective transport channels.

[0029] In some embodiments of the present invention, Aj is a group with the structure shown in formula (δ); in formula (δ), R1 and R2 are independently selected from hydrogen, halogen, halogen-substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C1-C5 alkyl ester, halogen-substituted or trihalomethyl-substituted or unsubstituted phenyl. In some embodiments, R1 and R2 are independently selected from F-substituted or Br-substituted or unsubstituted C1-C5 alkyl, F-substituted or trifluoromethyl-substituted phenyl or unsubstituted C1-C5 alkyl ester.

[0030]

[0031] In one embodiment, the structure of Aj is shown in any of equations (1) to (16):

[0032]

[0033]

[0034] In one embodiment, the polyelectrolyte material of the present invention has a structure of formula (A-1) or formula (A-2):

[0035]

[0036] The polyelectrolyte material provided by this invention improves cation selectivity through the synergistic effect of crown ethers and sulfonic acid groups. Specifically, the crown ether forms a positively charged complex structure with hydrated hydrogen ions or alkali metal ions through host-guest interactions, exhibiting a stronger electrostatic repulsion effect on divalent cations. Furthermore, the positively charged crown ether-cation complex structure and the negatively charged sulfonic acid groups exhibit electrostatic attraction, promoting the preferential passage of monovalent cations through hydrophilic channels, thereby significantly improving the selectivity of monovalent / divalent cations during electrodialysis.

[0037] This invention provides a method for preparing the above-mentioned polyelectrolyte material, comprising the following steps:

[0038] The polyelectrolyte material is obtained by polymerizing sulfonic acid-substituted aryl monomers, dibenzocrown ether monomers, and carbonyl-containing monomers under the action of a catalyst.

[0039] Specifically, the present invention dissolves sulfonic acid-substituted aryl monomer compounds, dibenzocrown ether monomer compounds and carbonyl-containing monomer compounds in a catalyst for polymerization, and then adds the reaction product to ethanol for purification. After filtration, washing and drying, the polyelectrolyte material is obtained.

[0040] In some embodiments of the present invention, sulfonic acid-substituted aryl monomer compounds, dibenzocrown ether monomer compounds, and carbonyl-containing monomer compounds are dissolved in a catalyst and subjected to a one-pot polymerization reaction on a stirred table. The resulting product is then added dropwise to ethanol for purification, filtered using a Buchner funnel, and the filter residue is washed with deionized water until neutral and dried to obtain the polyelectrolyte material.

[0041] In one embodiment, the polymerization temperature is 0°C to 10°C, and the polymerization time is 2 h to 48 h. In one embodiment, the molar ratio of the sulfonic acid-substituted aryl monomer compound, the dibenzocrown ether monomer compound, and the carbonyl-containing monomer compound is preferably 1:4:6.5, and the total mass of the sulfonic acid-substituted aryl monomer compound, the dibenzocrown ether monomer compound, and the carbonyl-containing monomer compound accounts for 10 wt% to 15 wt% of the total mass of the entire reaction system.

[0042] The catalyst described above comprises trifluoroacetic acid and trifluoromethanesulfonic acid, wherein the volume ratio of trifluoroacetic acid to trifluoromethanesulfonic acid is preferably 44:25. The catalyst of the present invention can be used after mixing with an organic solvent, effectively controlling the polymerization reaction. In one embodiment, the catalyst comprises trifluoroacetic acid, trifluoromethanesulfonic acid, and dichloromethane. In another embodiment, the catalyst comprises trifluoroacetic acid, dichloromethane, and trifluoromethanesulfonic acid, wherein the volume ratio of trifluoroacetic acid, dichloromethane, and trifluoromethanesulfonic acid is preferably 44:6:25.

[0043] In one embodiment, the sulfonic acid-substituted aryl monomer compound is selected from at least one of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium, 2,2'-bis(4-sulfonylbutoxy)biphenyl disodium, 2,2'-bis(3-sulfonylpropoxy)binaphthyl disodium, 2,2'-bis(4-sulfonylbutoxy)binaphthyl disodium, and 9,9-bis(3-sulfonylpropoxy)fluorene disodium.

[0044] In one embodiment, the above-mentioned dibenzocrown ether monomer compound is selected from at least one of dibenzo12crown4 ether, dibenzo18crown6 ether, dibenzo15crown5 ether, 2,3,8,9-dibenzo18crown6 ether, dibenzo21crown7 ether, dibenzo14crown4 ether, dibenzo24crown8 ether, and dibenzo30crown10 ether.

[0045] In one embodiment, the carbonyl-containing monomer compound is selected from at least one of hexafluoroacetone, 1,1,1-trifluoroacetone, 1,1,1-trifluoro-3-bromoacetone, 1,1,1-trifluoro-6-bromohexanone, 2,2,2-trifluoroacetophenone, perfluorobenzaldehyde, 1-(3,4-difluorophenyl)-2,2,2-trifluoroacetophenone, 1-(3,5-dichlorophenyl)-2,2,2-trifluoroacetophenone, 2,4,6-trifluorobenzaldehyde, 4'-trifluoromethyl-2,2,2-trifluoroacetophenone, 3'-trifluoromethyl-2,2,2-trifluoroacetophenone, 3,5-bis(trifluoromethyl)phenyl ketone, perfluoroacetophenone, 1,1,1-trifluoro-2-butanone, ethyl trifluoroacetate, and methyl trifluoroacetate.

[0046] The present invention also provides a cation-selective separation membrane, comprising the polyelectrolyte material described above or the polyelectrolyte material prepared by the above method. In one embodiment, the thickness of the cation-selective separation membrane is 20 μm to 400 μm.

[0047] The present invention also provides a method for preparing the above-mentioned cation-selective separation membrane, comprising: mixing the above-mentioned polyelectrolyte material with a polar organic solvent, and then coating and drying to obtain the above-mentioned cation-selective separation membrane. Specifically, the above-mentioned polyelectrolyte material is dissolved in a polar organic solvent to prepare a membrane solution; the membrane solution is coated in a mold, heated and dried, and then removed to obtain the above-mentioned cation-selective separation membrane.

[0048] In one embodiment, the concentration of the membrane solution is 5 wt%-30 wt%, meaning the concentration of the polyelectrolyte material in the polar organic solvent is 5 wt%-30 wt%. In one embodiment, the polar organic solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. In one embodiment, the drying temperature is 60°C to 80°C, and the drying time is 20 h to 40 h, preferably 24 h.

[0049] This invention provides a polyelectrolyte material, its preparation method, and a cation-selective separation membrane. The polyelectrolyte material provided by this invention, when applied to a cation-selective separation membrane, exhibits high cation separation performance. The preparation method is simple and suitable for large-scale industrial production. Experiments show that the cation-selective separation membrane made from the polyelectrolyte material provided by this invention has a high selective permeability (P0). (K+ / Mg2+) It reached 90.3; P (H+ / Fe2+) It reached 3153.

[0050] The polyelectrolyte material provided by this invention, starting from polymer molecular chain design and polymer membrane microstructure control, completely avoids the defects of surface modification processes. Traditional methods typically increase membrane density by improving crosslinking degree or grafting side chains, or introduce positively charged groups to enhance electrostatic repulsion. However, these methods significantly reduce ion transport capacity and increase energy consumption. Compared with traditional methods of controlling membrane structure, the introduction of crown ether rings containing a large number of oxygen atoms and sulfonic acid groups in this invention ensures that the prepared membrane has high cation selective separation performance. Among them, the crown ether group mainly realizes the selective function of cations, and the high-efficiency selective separation performance of cations can be further controlled according to the different types of crown ethers selected. The crown ether ring containing a large number of oxygen atoms has a complexing effect on both hydrated hydrogen ions and alkali metal ions, forming a positively charged complex, which maintains electroneutrality with the sulfonic acid group, improves the thermal stability of the membrane, and achieves high-efficiency selective transport of target ions. At the same time, this positively charged complex further improves the selectivity of monovalent / divalent cations of the membrane by occupying ion transport sites and electrostatic repulsion. Taking dibenzo-18 crown 6 ether as a monomer as an example, when two different cations (e.g., H) + and Fe 2+ Ion system, K + and Mg 2+ In the presence of an ionic system, hydrated hydrogen ions and K+ ions that complex with dibenzo-18-crown-6 ethers + Then it preferentially passes through this ion-selective transport channel, while a specific monovalent ion (H) will preferentially pass through it. + or K + When passing through this channel, larger divalent ions have difficulty passing through it; on the other hand, when monovalent ions form a complex with the crown ether, this complex structure is positively charged, exerting a strong electrostatic repulsion on the divalent ions coexisting in the separation system. + or K + Removal from the crown ether ring is achieved with the assistance of sulfonic acid groups and an electric field. Through the synergistic effect of host-guest interactions within the crown ether and ion transport assisted by sulfonic acid groups, highly efficient selectivity for monovalent / divalent cations is ultimately obtained.

[0051] In this invention, the microstructure of the constructed membrane is controlled through the structural design of the polyelectrolyte. Utilizing molecular self-assembly properties, an ion-selective transport channel containing both crown ether groups and sulfonic acid groups is constructed. Furthermore, by leveraging the host-guest recognition interaction between the crown ether groups and cations, the channel exhibits pore size sieving and electrostatic repulsion for high-valence cations with larger hydrated ionic radii, ultimately ensuring that the prepared crown ether-type mono / divalent cation selective separation membrane possesses both high ion flux and selectivity. Additionally, by changing the type of crown ether group, selective separation of different specific cations can be achieved. The membrane's cation separation performance is highly tunable to meet the application requirements of different cation separation systems. In summary, the innovation of this invention lies not only in achieving high ion flux and selectivity, but also in its simple membrane fabrication process, homogeneous membrane structure requiring no subsequent modification, strong controllability, and promising prospects for large-scale industrial production. Attached Figure Description

[0052] Figure 1 The above is the 1H NMR spectrum of the polyelectrolyte obtained in Example 1;

[0053] Figure 2 Thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 1;

[0054] Figure 3 The tensile strength curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 1;

[0055] Figure 4 Small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 1;

[0056] Figure 5 An atomic force microscope image of the crown ether mono / divalent cation selective separation membrane prepared in Example 1;

[0057] Figure 6 The hydrophilic phase width distribution diagram is shown for the crown ether mono / divalent cation selective separation membrane prepared in Example 1.

[0058] Figure 7 The 1H NMR spectrum of the polyelectrolyte obtained in Example 2;

[0059] Figure 8 Thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 2;

[0060] Figure 9 Small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 2;

[0061] Figure 10The 1H NMR spectrum of the polyelectrolyte obtained in Example 3;

[0062] Figure 11 Thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 3;

[0063] Figure 12 Small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 3;

[0064] Figure 13 The 1H NMR spectrum of the polyelectrolyte obtained in Example 4;

[0065] Figure 14 Thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 4;

[0066] Figure 15 Small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 4;

[0067] Figure 16 The image shows the proton NMR spectrum of the polyelectrolyte obtained in Example 7. Detailed Implementation

[0068] This invention discloses a polyelectrolyte material, its preparation method, and a cation-selective separation membrane. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments; those skilled in the art will clearly be able to modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0069] The present invention will be further described below with reference to the embodiments:

[0070] Example 1

[0071] This embodiment provides a crown ether type mono / divalent cation selective separation membrane, and the preparation route is as follows:

[0072]

[0073] 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium salt, and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone were added sequentially to a 100 mL round-bottom flask. 17.6 mL of trifluoroacetic acid and 2.4 mL of dichloromethane were added to dissolve the precipitate. 10 mL of trifluoromethanesulfonic acid was added at 0 °C, and the reaction was carried out for 8 hours. The product was precipitated in ethanol, washed thoroughly with deionized water, and filtered through a Buchner funnel to obtain a white solid. The solid was dried in an electric hot air drying oven at 60–80 °C for 24 hours to obtain the crown ether polyelectrolyte.

[0074] The polyelectrolyte product was subjected to nuclear magnetic resonance testing, and the results are as follows: Figure 1 As shown, Figure 1 The image shows the 1H NMR spectrum of the polyelectrolyte obtained in Example 1. The 1H NMR spectrum was recorded using an AVANCE AV400 Bruker instrument with deuterated dimethyl sulfoxide (DMSO-d6, tetramethylsilane as internal standard) as the solvent.

[0075] Take 1g of the above polyelectrolyte material, add 10mL of N-methylpyrrolidone, and dissolve it completely to obtain a uniform and transparent membrane solution. Coat the membrane solution onto a clean glass plate and dry it at 80℃ to form a membrane. Place the glass plate in deionized water and immerse it completely. The membrane swells and falls off the glass plate to obtain a crown ether type mono / divalent cation selective separation membrane.

[0076] The thermal stability of the crown ether type mono / divalent cation selective separation membrane was tested, and the results are as follows: Figure 2 As shown, Figure 2 The thermogravimetric analysis (TGA) curve of the crown ether type mono / divalent cation selective separation membrane obtained in Example 1 is shown. The TGA analyzer was a TGA Q5000IR (TA Instrunebts), and the data was recorded under a nitrogen atmosphere at a heating rate of 10 °C min⁻¹. This demonstrates that, with a molar ratio of sulfonic acid-substituted aryl monomer, dibenzocrown ether monomer, and carbonyl-containing monomer of 1:4:6.5, the positively charged crown ether-cation complex structure of the membrane exhibits electrostatic attraction with the negatively charged sulfonic acid group, improving the thermal stability of the sulfonic acid-containing side chain while maintaining high thermal stability of the main chain.

[0077] The crown ether type mono / divalent cation selective separation membrane was subjected to room temperature tensile strength testing, such as... Figure 3 As shown, Figure 3The image shows the tensile strength curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 1. Tensile strength was recorded at room temperature using a dynamic mechanical analyzer (Q800, TA Instrunebts). This demonstrates that, with a molar ratio of sulfonic acid-substituted aryl monomer, dibenzocrown ether monomer, and carbonyl-containing monomer of 1:4:6.5, the positively charged crown ether-cation complex structure exhibits electrostatic attraction with the negatively charged sulfonic acid group, resulting in high tensile strength and elongation at break of the prepared crown ether type mono / divalent cation selective separation membrane.

[0078] Microphase separation tests were performed on the crown ether type mono / divalent cation selective separation membrane, and the results are as follows: Figures 4-6 As shown, Figure 4 This is a small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 1. Figure 5 This is an atomic force microscopy image of the crown ether mono / divalent cation selective separation membrane prepared in Example 1. Figure 6 This is a width distribution diagram of the hydrophilic phase. Small-angle X-ray scattering was performed by Saxesess mc2, Anton Paar, and atomic force microscopy was performed by Dimension Icon, Bruker. This demonstrates that the crown ether type mono / divalent cation selective separation membrane achieves hydrophilic-hydrophobic phase separation, and that the positively charged crown ether-cation complex structure and the negatively charged sulfonic acid group exhibit electrostatic attraction. The crown ether and sulfonic acid groups together form a hydrophilic ion transport channel.

[0079] The cation separation performance of the crown ether type mono / divalent cation selective separation membrane obtained in this embodiment was tested by electrodialysis. The electrodialysis conditions were as follows: KCl-MgCl2 system: 100 mL of a mixed solution of 0.1 mol / L KCl and 0.1 mol / L MgCl2 in the desalination chamber, 100 mL of deionized water in the concentration chamber, and 0.3 mol / L Na2SO4 solution in the polarization chamber. The effective membrane area was 7.07 cm². 2 Current density 2 mA / cm 2 The electrodialysis time was 1 hour; the HCl-FeCl2 system consisted of 100 mL of a mixed solution of 1 mol / L HCl and 0.27 mol / L FeCl2 in the desalination chamber, 100 mL of a 0.01 mol / L HCl solution in the concentration chamber, and a 0.3 mol / L Na2SO4 solution in the polarization chamber. The effective membrane area was 21 cm². 2 Current density 10 mA / cm 2 The electrodialysis time was 1 hour.

[0080] The method for calculating ion flux is shown in Formula 1:

[0081]

[0082] Where J is the ion flux; C0 represents the cation concentration at 0 hours in the concentration chamber; C t The concentration of cations in the concentration chamber is represented by t hours; V is the volume of the solution in the concentration chamber; A m The effective area of ​​the test membrane is represented by t; the test duration is t.

[0083] The method for calculating permeability (P) is shown in Formula 2:

[0084]

[0085] in, This represents the ion flux of monovalent ions during the test period; This represents the ion flux of divalent ions during the test period; This indicates the initial concentration of monovalent ions in the desalination chamber; This indicates the initial concentration of divalent ions in the desalination chamber.

[0086] Electrodialysis testing revealed that the K ion flux of the product in Example 1 was [value missing]. h -1 Choose permeability The H ion flux of the product in Example 1 was measured to be: mol m -2 h -1 Choose permeability

[0087] Example 2

[0088] The only difference from Example 1 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 1 were replaced with 3.676 g (10.20 mmol) of dibenzo-18 crown 6 ether, 1.533 g (3.40 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone. The rest of the preparation method is the same as in Example 1. The polyelectrolyte product was subjected to nuclear magnetic resonance testing, and the results are as follows: Figure 7 As shown, Figure 7 The image shows the proton NMR spectrum of the polyelectrolyte obtained in Example 2.

[0089] The thermal stability of the crown ether type mono / divalent cation selective separation membrane was tested, and the results are as follows: Figure 8As shown, Figure 8 The thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 2 shows that the positively charged crown ether-cation complex structure has an electrostatic attraction with the negatively charged sulfonic acid group, and improves the thermal stability of the side chain with sulfonic acid group.

[0090] Small-angle X-ray scattering (SAXS) was performed on the crown ether type mono / divalent cation selective separation membrane, and the results are as follows: Figure 9 As shown, Figure 9 The small-angle X-ray scattering pattern of the crown ether mono / divalent cation selective separation membrane prepared in Example 2 demonstrates that the crown ether and sulfonic acid groups together form a highly periodic hydrophilic ion transport channel.

[0091] Electrodialysis testing revealed that the H ion flux of the product in Example 2 was [value missing]. Choose permeability

[0092] Example 3

[0093] The only difference from Example 1 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 1 were replaced with 3.269 g (9.07 mmol) of dibenzo-18 crown 6 ether, 2.149 g (4.53 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone. The rest of the preparation method is the same as in Example 1. The polyelectrolyte product was subjected to NMR testing, and the results are as follows: Figure 10 As shown, Figure 10 The image shows the proton NMR spectrum of the polyelectrolyte obtained in Example 3.

[0094] The thermal stability of the crown ether type mono / divalent cation selective separation membrane was tested, and the results are as follows: Figure 11 As shown, Figure 11 The thermogravimetric analysis curve of the crown ether type mono / divalent cation selective separation membrane prepared in Example 3 shows that when the ratio of crown ether to sulfonic acid is 2:1, the side chain with sulfonic acid group has high thermal stability.

[0095] Small-angle X-ray scattering (SAXS) was performed on the crown ether type mono / divalent cation selective separation membrane, and the results are as follows: Figure 12 As shown, Figure 12The small-angle X-ray scattering (SAXS) pattern of the crown ether mono / divalent cation selective separation membrane prepared in Example 3 demonstrates that the crown ether and sulfonic acid groups together form a highly periodic hydrophilic ion transport channel.

[0096] Electrodialysis testing revealed that the H ion flux of the product in Example 3 was [value missing]. Choose permeability

[0097] Example 4

[0098] The only difference from Example 1 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 1 were replaced with 2.451 g (6.80 mmol) of dibenzo-18 crown 6 ether, 3.226 g (6.80 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone. The rest of the preparation method is the same as in Example 1. The polyelectrolyte product was subjected to nuclear magnetic resonance testing, and the results are as follows: Figure 13 As shown, Figure 13 The image shows the proton NMR spectrum of the polyelectrolyte obtained in Example 4.

[0099] The thermal stability of the crown ether type mono / divalent cation selective separation membrane was tested, and the results are as follows: Figure 14 As shown, when the ratio of crown ether to sulfonic acid is 1:1, the side chain with sulfonic acid group is easily degraded, and the addition of crown ether monomer does not have a significant impact on the thermal stability of the side chain.

[0100] Small-angle X-ray scattering (SAXS) was performed on the crown ether type mono / divalent cation selective separation membrane, and the results are as follows: Figure 15 As shown, Figure 15 The small-angle X-ray scattering (SAXS) image of the crown ether mono / divalent cation selective separation membrane prepared in Example 4 shows that no interaction force is generated between the crown ether and the sulfonic acid groups, and the sulfonic acid groups aggregate to form spherical hydrophilic water.

[0101] Electrodialysis testing revealed that the H+ ion flux of the product in Example 4 was [value missing]. Choose permeability

[0102] Example 5

[0103] The only difference from Example 1 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 1 were replaced with 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.366 g (2.72 mmol) of 2,2'-bis(4-sulfonylbutoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone. The rest of the preparation method is the same as in Example 1. Electrodialysis testing showed that the K ion flux of the product in Example 5 was [value missing]. Choose permeability

[0104] Example 6

[0105] The only difference from Example 1 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 1 were replaced with 3.921 g (10.88 mmol) of dibenzo-18 crown 6 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 3.078 g (17.68 mmol) of 2,2,2-trifluoroacetophenone. The rest of the preparation method is the same as in Example 1. Electrodialysis testing showed that the K ion flux of the product in Example 6 was [value missing]. Choose permeability

[0106] Example 7

[0107] This embodiment provides a crown ether type mono / divalent cation selective separation membrane, and the preparation route is as follows:

[0108]

[0109] 3.442 g (10.88 mmol) of dibenzo-15 crown 5 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium salt, and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone were sequentially added to a 100 mL round-bottom flask. 17.6 mL of trifluoroacetic acid and 2.4 mL of dichloromethane were added to dissolve the precipitate. 10 mL of trifluoromethanesulfonic acid was added at 0 °C, and the reaction was allowed to proceed for 9 hours. The product precipitated in ethanol, washed thoroughly with deionized water, and filtered through a Buchner funnel to obtain a white solid. This solid was dried in an electric hot air drying oven at 80 °C for 24 hours to obtain the crown ether type mono / divalent cation selective separation membrane polyelectrolyte. Nuclear magnetic resonance (NMR) testing was performed on the polyelectrolyte product, and the results are as follows: Figure 16 As shown, Figure 16 The image shows the proton NMR spectrum of the polyelectrolyte obtained in Example 7.

[0110] Take 1g of the above polyelectrolyte material, add 10mL of N-methylpyrrolidone, and dissolve thoroughly to obtain a uniform and transparent membrane solution. Coat the membrane solution onto a clean glass plate, dry it at 80℃ to form a film, and immerse the glass plate in deionized water. The membrane swells and detaches from the glass plate, yielding a crown ether type mono / divalent cation selective separation membrane. Electrodialysis testing showed that the H ion flux of the product in Example 7 was [value missing]. Choose permeability

[0111] Example 8

[0112] The only difference from Example 7 is that in the preparation of the crown ether type mono / divalent cation selective separation membrane, the 3.442 g (10.88 mmol) of dibenzo-15 crown 5 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone used in Example 7 were replaced with 2.960 g (10.88 mmol) of dibenzo-12 crown 4 ether, 1.291 g (2.72 mmol) of 2,2'-bis(3-sulfonylpropoxy)biphenyl disodium and 1.981 g (17.68 mmol) of 1,1,1-trifluoroacetone. The rest of the preparation method is the same as in Example 7. Electrodialysis testing showed that the H ion flux of the product in Example 8 was [value missing]. Choose permeability

[0113] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A polyelectrolyte material, characterized in that it has a structure as shown in formula (A): wherein x = 0.01 ~ 0.99, n represents a polymerization degree; Af is a group having a structure as shown in formula (α): wherein Aa is a phenyl group, a naphthyl group or an anthracene group; Ab is a group having a structure as shown in any one of formula (a) to formula (e): wherein Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl group or an anthracene group; Aa is a phenyl group, a naphthyl Formula (A); wherein ​ Ab is a group of the structure shown in Formula (a) or Formula (β); in Formula (a), Af is a C6-Ci2aryl group; m and n are independently integers from 1 to 5; in Formula (β), Aa is a C6-Ci2aryl group; z and q are independently integers from 1 to 5. 22 22 Ab is a group of the structure shown in Formula (a) or Formula (β); in Formula (a), Af is a C6-Ci2aryl group; m and n are independently integers from 1 to 5; in Formula (β), Aa is a C6-Ci2aryl group; z and q are independently integers from 1 to 5. 22 22 Ab is a group of the structure shown in Formula (a) or Formula (β); in Formula (a Formula (a); Formula (β); ​ Formula (γ); ​ Formula (δ).

2. The polyelectrolyte material of claim 1, wherein, ​ ​ ​ 3. The polyelectrolyte material of claim 1, wherein ​ formula (a); formula (b); formula (c); formula (d); Formula (e).

4. The polyelectrolyte material of claim 1, wherein, ​ Formula (g); Formula (h); Formula (i); Formula (j); Formula (k); Formula (l); Formula (m); Formula (n).

5. The polyelectrolyte material of claim 1, wherein, ​ Formula (1); Formula (2); Formula (3); Formula (4); Formula (5); Formula (6); Formula (7); Formula (8); Formula (9); Formula (10); Formula (11); Formula (12); Formula (13); Formula (14); Formula (15); Formula (16). ​ formula (A-1); Formula (A-2).

7. A method for producing a polyelectrolyte material, characterized by, ​ ​ ​ ​ ​ ​ 8. The method of claim 7, wherein, ​ The polymerization reaction is performed for 2 hours to 48 hours.

9. A cation-selective separation membrane characterized in that, The polymeric electrolyte material includes the polymeric electrolyte material of any one of claims 1 to 6 or the polymeric electrolyte material prepared by the method of any one of claims 7 to 8.

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