Preparation method of high-flux monovalent selective double-sided chain type anion exchange membrane

Abstract

The application relates to the field of polymer high molecular materials, and particularly discloses a preparation method of a high-flux monovalent selective double-side chain type anion exchange membrane. In the preparation method, under the condition of ensuring the proper selectivity of an ion membrane, isophthaldehyde ketone structure and rigid benzimidazole structure are introduced into a polyarylene ether sulfone main chain, long side chains, twisted folding structures and rigid structures are utilized, the intermolecular stacking is prevented, the structure relaxation and the loss of micropores are prevented, free volumes are generated in the polymer membrane, micropore channels (ion channels) are formed, the high-efficiency transmission of monovalent ions is promoted, and a kind of ion exchange membrane with stable structure, high permeation flux and selectivity is constructed.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane, belonging to the field of membrane technology. Background Technology

[0002] Improving the level of precise ion separation technology is of great significance to the sustainable development of chemical industry production.

[0003] Ocean energy is a renewable energy source found in the ocean, including tidal energy, wave energy, and salinity gradient energy. Among these, salinity gradient energy has the highest energy density of any ocean energy source. Salinity gradient energy refers to the chemical potential difference energy existing between seawater and freshwater, or between solutions with different salt concentrations. It is estimated that there is approximately 2 TW of abundant salinity gradient energy worldwide, while my country's potential usable salinity gradient energy is approximately 0.1 TW, mainly concentrated at the estuaries of major rivers.

[0004] To capture this salinity gradient energy, efficient energy conversion technologies need to be developed. Reverse electrodialysis (RED) is the most common and promising salinity gradient energy conversion technology. RED technology places ion-selective permeable membranes between salt solutions of different concentrations. Utilizing the concentration difference between different ions, they migrate directionally between the ion exchange membranes, thereby directly converting chemical potential energy into electrical energy. It has advantages such as high energy density, low membrane fouling, and low investment cost.

[0005] Currently, the development of reverse electrodialysis technology has made significant progress, but it still faces some challenges. (1) Poor ion selectivity. Existing commercial membranes are more suitable for use in electrodialysis processes, but are not very applicable to reverse electrodialysis. The RED process requires higher ion selectivity and less mechanical strength. (2) Low power generation efficiency. The low power generation efficiency is because the membrane used in RED requires extremely low resistance, but low-resistance membranes are expensive and prone to swelling, so a membrane with suitable ion flux is required.

[0006] Under the condition of ensuring suitable selectivity of ion exchange membrane, isobenzofuranone structure, rigid benzimidazole structure, etc. are introduced into the polyarylether sulfone backbone. By utilizing long side chains, twisted folding structure and rigid structure, the molecules cannot be effectively stacked, thus preventing structural relaxation and loss of micropores. This generates free volume in the polymer membrane and forms micropores (ion channels) to help promote the efficient transport of monovalent ions, thereby constructing a type of structurally stable ion exchange membrane with high permeation flux and selectivity. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a method for a side-chain anion exchange membrane with a twisted structure.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane includes the following steps:

[0010] Step (1) Preparation of monomer (I):

[0011] PPH-1, as shown in formula (I), was prepared by reacting n-propylamine with 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) under a nitrogen atmosphere and at 160 °C via reflux.

[0012]

[0013] Step (2) Preparation of monomer (II):

[0014] PPH-2 of formula (II) was prepared by reacting pentamidine with 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) under a nitrogen atmosphere and at 170 °C via reflux.

[0015]

[0016] Step (3) Preparation of monomer (III):

[0017] Heptamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) were reacted under a nitrogen atmosphere and refluxed at 180 °C to prepare PPH-3 as shown in formula (III);

[0018]

[0019] Step (4) Preparation of monomer (IV):

[0020] 1-(3-aminopropyl)imidazolium and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) were reacted under a nitrogen atmosphere and refluxed at 195 °C to prepare PPH-4 as shown in formula (IV).

[0021]

[0022] Step (5) Preparation of monomer (V):

[0023] 3,3'-Diaminobenzidine, p-hydroxybenzaldehyde, and sodium metabisulfite were reacted under a nitrogen atmosphere at 80°C to prepare DBIM as shown in formula (V);

[0024]

[0025] Step (6) Preparation of the main structural chain:

[0026] PPH-1 monomer of formula (I), PPH-2 monomer of formula (II), PPH-3 monomer of formula (III), 4,4'-difluorodiphenyl sulfone monomer, PPH-4 monomer of formula (V), and DBIM monomer are added respectively, and the polyarylene ether sulfone with an amino-phenolphthalein structure in the main chain is obtained by solvent co-condensation, as shown in formula (VI); wherein, the total molar ratio of PPH-1 or PPH-2 or PPH-3, PPH-4 and DBIM to the molar ratio of 4,4'-difluorodiphenyl sulfone is 1:1, and the molar ratio of monomers (I), (II), and (III), PPH-4 and DBIM is x:y:100-xy = 100%~70%:70%~40%:0%~40%; the number average molecular weight Mn of the polyarylene ether sulfone is 50000~120000;

[0027]

[0028] Step (7) Alkyl functionalization of the main structural chain and preparation of anion exchange membrane:

[0029] The product (VI) prepared in step (6) is dissolved in an organic solvent, and then 1-bromopropane (VIII), 1-bromopentane (IX), and 1-bromoheptane (X) are added in a ratio of 1:2 and stirred for a certain period of time. After standing and degassing, a casting solution is obtained. The mass-volume concentration of polyarylene sulfone in the casting solution is 3-8%. The organic solvent is one or more of DMF, DMAc, and NMP. The obtained casting solution is poured onto a glass plate and kept at 40-200℃ for 12-96 hours to achieve in-situ reaction and drying. After cooling, the film is peeled off from the glass plate in water to obtain an alkyl-functionalized anion exchange membrane with the structural formula shown in formula (VII) and a thickness of 70-150 μm.

[0030]

[0031]

[0032] Where x:y:100-xy = 100%~70%:70%~40%:0%~40%.

[0033] As a preferred embodiment, step (1) of the present invention is specifically implemented as follows: In a reaction vessel, n-propylamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 40°C for 48 hours to obtain the PPH-1 monomer shown in formula (I).

[0034] As a further preferred option, in step (1), the molar ratio of n-propylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:1, with the most preferred ratio being 2:1.

[0035] As a further preferred option, in step (1), the dilute hydrochloric acid solution is a hydrochloric acid aqueous solution of 0.1 to 0.5 mol / L, and most preferably a hydrochloric acid aqueous solution of 0.2 mol / L.

[0036] As a further preferred embodiment, in step (1), the separation and purification are carried out as follows: under a nitrogen atmosphere, the mixture is heated to reflux and maintained for 12-48 hours, then cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, resulting in a white precipitate. The precipitate is washed with water 3-5 times and then vacuum dried at 30-80°C (more preferably 50°C) for 24-48 hours (more preferably 48 hours).

[0037] Preferably, step (2) of the present invention is specifically implemented as follows: In a reaction vessel, pentylamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 40°C for 48 hours to obtain the PPH-2 monomer shown in formula (II).

[0038] As a further preferred option, in step (2), the molar ratio of pentylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:1, with the most preferred ratio being 2:1.

[0039] As a further preferred option, in step (2), the dilute hydrochloric acid solution is a hydrochloric acid aqueous solution of 0.1 to 0.5 mol / L, and most preferably a hydrochloric acid aqueous solution of 0.2 mol / L.

[0040] As a further preferred embodiment, in step (2), the separation and purification are carried out as follows: under a nitrogen atmosphere, the mixture is heated to reflux and maintained for 12-48 hours, then cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, resulting in a white precipitate. The precipitate is washed with water 3-5 times and then vacuum dried at 30-80°C (more preferably 50°C) for 24-48 hours (more preferably 48 hours).

[0041] As a preferred embodiment, step (3) of the present invention is specifically implemented as follows: In a reaction vessel, heptamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 40°C for 48 hours to obtain the PPH-3 monomer shown in formula (III).

[0042] As a further preferred option, in step (3), the molar ratio of pentylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:1, with the most preferred ratio being 2:1.

[0043] As a further preferred option, in step (3), the dilute hydrochloric acid solution is a hydrochloric acid aqueous solution of 0.1 to 0.5 mol / L, and most preferably a hydrochloric acid aqueous solution of 0.2 mol / L.

[0044] As a further preferred embodiment, in step (3), the separation and purification are carried out as follows: under a nitrogen atmosphere, the mixture is heated to reflux and maintained for 12-48 hours, then cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, resulting in a white precipitate. The precipitate is washed with water 3-5 times and then vacuum dried at 30-80°C (more preferably 50°C) for 24-48 hours (more preferably 48 hours).

[0045] Preferably, step (4) of the present invention is specifically implemented as follows: In a reaction vessel, 1-(3-aminopropyl)imidazolium and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into deionized water, resulting in a precipitate. The precipitate is then filtered, recrystallized from the solution, and dried under vacuum at 40°C for 48 hours to obtain the PPH-4 monomer shown in formula (IV).

[0046] As a further preferred embodiment, in step (4), the molar ratio of pentylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:1, with the most preferred ratio being 2:1.

[0047] Preferably, step (5) of the present invention is specifically implemented as follows: In a reaction vessel, 3,3'-diaminobenzidine and p-hydroxybenzaldehyde are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature, the insoluble solids are filtered off, the solution is poured into deionized water, washed 3-5 times with deionized water, and the precipitate is vacuum dried at 40°C for 48 hours to obtain the DBIM monomer shown in formula (V).

[0048] As a further preferred embodiment, in step (5), the molar ratio of 3,3'-diaminobenzidine to 3-hydroxybenzaldehyde is 1:2-4, with the most preferred ratio being 1:2.5.

[0049] As a further preferred embodiment, in step (5), the separation and purification are carried out as follows: under a nitrogen atmosphere, the mixture is heated to reflux and maintained for 12-48 hours, then cooled to room temperature, the insoluble solids are filtered off, the solution produces a precipitate in deionized water, the precipitate is washed with water 3-5 times, and the precipitate is vacuum dried at 30-80°C (more preferably 50°C) for 24-48 hours (more preferably 48 hours).

[0050] Preferably, step (6) of the present invention is specifically implemented as follows: 4,4'-difluorodiphenyl sulfone is added to the reaction vessel, and PPH-1, PPH-2, PPH-3 and PPH-4 shown in formula (I)(II)(III) and formula (IV) are added respectively, as well as DBIM shown in formula (V), polar aprotic solvent B, salt-forming agent potassium carbonate and dehydrating agent. The reaction is carried out under nitrogen protection at 100-180°C for 4-24 hours. After the reaction is completed, the main chain polyarylene ether sulfone is obtained by separation and drying.

[0051] As a further preferred option, in step (6), the polar aprotic solvent B is at least one of N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0052] As a further preferred option, in step (6), the mass amount of potassium carbonate as the salt-forming agent is 5.0-6.5 g / 20 mmol, calculated as the amount of 4,4'-difluorodiphenyl sulfone.

[0053] As a further preferred embodiment, the dehydrating agent is toluene, and the volume ratio of toluene to polar aprotic solvent B is 0.2 to 0.7:1.

[0054] Preferably, in step (7), the molar ratio of polyarylether sulfone to 1-bromopropane, 1-bromopentane, and 1-bromoheptane is 0.4 to 1.00:1.

[0055] As a further preferred option, in step (7), the molar ratio of polyarylether sulfone to 1-bromopropane, 1-bromopentane, and 1-bromoheptane is 0.6 to 1.00:1.

[0056] Preferably, in step (7), the mass-volume concentration of polyarylether sulfone in the casting solution is 5%.

[0057] As a preferred option, in step (7), the reaction conditions are: reaction at 70°C for 18-36 hours.

[0058] As a further preferred option, in step (7), the reaction conditions are: reaction at 70°C for 24 hours.

[0059] The side-chain anion exchange membrane prepared by this invention has advantages such as good ion conductivity, good dimensional stability, and high selectivity for monovalent anions, and has broad application prospects, especially in the field of electrodialysis.

[0060] Compared with the prior art, the advantages of this invention are:

[0061] (1) The monovalent anion high permeation anion exchange membrane of the present invention induces hydrophilic / hydrophobic microphase separation to construct a continuous ion transport channel of appropriate size by adjusting the ratio of the two side chains (hydrophobic segments and hydrophilic segments) and the length of the hydrophobic alkyl chain on the side chain, thereby promoting the selective transport of monovalent ions and making the ion membrane have good monovalent anion selectivity.

[0062] (2) The monovalent anion high permeation anion exchange membrane of the present invention has a rigid and twisted structure containing N-ring QA cations, and the molecular chains cannot be effectively stacked, thus forming a unique ion channel with selective ion transport. It has good selectivity and high monovalent anion flux.

[0063] The present invention discloses a monovalent anion high permeation anion exchange membrane, which introduces appropriate free volume or micropores into the membrane to reduce the ion conduction resistance within the membrane and achieve a relatively high conductivity at a low IEC, thus giving the membrane a low surface resistance; at the same time, the homogeneous membrane structure formed by the chemical bonds between the conductive side chains and the rigid main chain ensures the mechanical stability of the membrane. Detailed Implementation

[0064] To further illustrate the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific examples.

[0065] Example 1

[0066] Preparation of monomer (I): 11.8 mL (144 mmol) of n-propylamine was weighed into a reaction vessel, and then 22.896 g (72 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-1 monomer shown in formula (I).

[0067] Preparation of monomer (IV): 9 g (72 mmol) of 1-(3-aminopropyl)imidazolium was weighed into a reaction vessel, and then 11.448 g (36 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-4 monomer shown in formula (I).

[0068] Preparation of monomer (V): 10.6 g (0.0495 mol) of 3,3'-diaminobenzidine and 24.0 g (0.1967 mol) of p-hydroxybenzaldehyde, along with 4.75 g of sodium metabisulfite dissolved in ethanol, were added to a reaction vessel. The mixture was heated to 80 °C under a nitrogen atmosphere and maintained for 24 h, then cooled to room temperature. After filtration to remove insoluble solids, the clear solution was poured into deionized water. Finally, the solution was filtered with deionized water and washed five times. After complete drying, the DBIM monomer shown in formula (V) was obtained.

[0069] Preparation of the main chain: 5.08 g (20 mmol) of 4,4'-difluorodiphenyl sulfone, 0.718 g (2 mmol) of PPH-1 monomer, 10.24 g (16 mmol) of PPH-4 monomer, and 1.266 g (2 mmol) of DBIM monomer were added to a 250 mL three-necked round-bottom flask equipped with a water separator. NMP (80 mL) was used as the solvent, and 5.5 g (40 mmol) of K₂CO₃ and 60 mL of toluene were added as the catalyst and water-carrying agent, respectively. The reaction was carried out at 135 °C for 6 h under N₂ atmosphere, followed by a reaction at 165 °C for 12 h. After the solution cooled to room temperature, it was poured into 300 mL of ethanol and flocculated under high-speed stirring to obtain a precipitate. After filtration, a yellow solid was obtained, which was repeatedly washed with ethanol and water, and then dried under vacuum at 80 °C for 24 h to obtain 17.304 g of polyarylethersulfone main chain polymer.

[0070] Preparation of anion exchange membrane: Weigh 5 g of polyarylether sulfone polymer into a round-bottom three-necked flask, dissolve it in 30 mL of NMP solvent, and stir magnetically at 80 °C until completely dissolved. Then add 0.976 g of 1-bromopropane and stir to obtain a casting solution. Degas the casting solution and pour the degassed casting solution onto a clean glass mold. Dry the mold at 70 °C for 24 h to form a membrane, thus obtaining the polyarylether sulfone anion exchange membrane.

[0071] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistivity, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made apparatus. The results are shown in Table 1. (For specific testing methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164)

[0072] Example 2

[0073] Monomer preparation: The same preparation process as in Example 1 was used.

[0074] Main chain preparation: The same preparation process as in Example 1 was used.

[0075] Preparation of anion exchange membrane: The same preparation process as in Example 1 was used, except that 1.198 g of 1-bromopentane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0076] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0077] Example 3

[0078] Monomer preparation: The same preparation process as in Example 1 was used.

[0079] Main chain preparation: The same preparation process as in Example 1 was used.

[0080] Preparation of anion exchange membrane: The same preparation process as in Example 1 was used, except that 1.42 g of 1-bromoheptane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0081] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0082] Example 4

[0083] Preparation of monomer (II): 17.42 mL (144 mmol) of pentylamine was weighed into a reaction vessel, and then 22.896 g (72 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-2 monomer shown in formula (II).

[0084] Preparation of monomer (IV): 9 g (72 mmol) of 1-(3-aminopropyl)imidazolium was weighed into a reaction vessel, and then 11.448 g (36 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-4 monomer shown in formula (I).

[0085] Preparation of monomer (V): 10.6 g (0.0495 mol) of 3,3'-diaminobenzidine and 24.0 g (0.1967 mol) of p-hydroxybenzaldehyde, along with 4.75 g of sodium metabisulfite dissolved in ethanol, were added to a reaction vessel. The mixture was heated to 80 °C under a nitrogen atmosphere and maintained for 24 h, then cooled to room temperature. After filtration to remove insoluble solids, the clear solution was poured into deionized water. Finally, the solution was filtered with deionized water and washed five times. After complete drying, the DBIM monomer shown in formula (V) was obtained.

[0086] Preparation of the main chain: 5.08 g (20 mmol) of 4,4'-difluorodiphenyl sulfone, 0.774 g (2 mmol) of PPH-2 monomer, 10.24 g (16 mmol) of PPH-4 monomer, and 1.266 g (2 mmol) of DBIM monomer were added to a 250 mL three-necked round-bottom flask equipped with a water separator. NMP (80 mL) was used as the solvent, and 5.5 g (40 mmol) of K₂CO₃ and 60 mL of toluene were added as the catalyst and water-carrying agent, respectively. The reaction was carried out at 135 °C for 6 h under N₂ atmosphere, followed by a reaction at 165 °C for 12 h. After the solution cooled to room temperature, it was poured into 300 mL of ethanol and flocculated under high-speed stirring to obtain a precipitate. After filtration, a yellow solid was obtained, which was repeatedly washed with ethanol and water, and then dried under vacuum at 80 °C for 24 h to obtain 17.36 g of polyarylethersulfone main chain polymer.

[0087] Preparation of anion exchange membrane: 5 g of polyarylether sulfone polymer was weighed into a round-bottom three-necked flask and dissolved in 30 mL of NMP solvent. The solution was magnetically stirred at 80 °C until completely dissolved. Then, 0.972 g of 1-bromopropane was added and stirred to obtain a casting solution. The casting solution was degassed and then poured into a clean glass mold. The mold was dried at 70 °C for 24 h to form a membrane, thus obtaining a polyarylether sulfone-based anion exchange membrane.

[0088] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0089] Example 5

[0090] Monomer preparation: The same preparation process as in Example 4 was used.

[0091] Main chain preparation: The same preparation process as in Example 4 was used.

[0092] Preparation of anion exchange membrane: The same preparation process as in Example 4 was used, except that 1.20 g of 1-bromopentane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0093] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0094] Example 6

[0095] Monomer preparation: The same preparation process as in Example 4 was used.

[0096] Main chain preparation: The same preparation process as in Example 4 was used.

[0097] Preparation of anion exchange membrane: The same preparation process as in Example 4 was used, except that 1.43 g of 1-bromopentane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0098] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0099] Example 7

[0100] Preparation of monomer (III): 21.31 mL (144 mmol) of heptamine was weighed into a reaction vessel, and then 22.896 g (72 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-3 monomer shown in formula (II).

[0101] Preparation of monomer (IV): 9 g (72 mmol) of 1-(3-aminopropyl)imidazolium was weighed into a reaction vessel, and then 11.448 g (36 mmol) of 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) was added. The mixture was heated to reflux under a nitrogen atmosphere and maintained for 48 h. Then it was cooled to room temperature and slowly poured into an ice-water mixture. Then 0.2 M dilute hydrochloric acid was added dropwise to neutralize the mixture. A white precipitate appeared. The precipitate was washed with water 5 times and dried under vacuum at 50 °C for 24 h to obtain the PPH-4 monomer shown in formula (I).

[0102] Preparation of monomer (V): 10.6 g (0.0495 mol) of 3,3'-diaminobenzidine and 24.0 g (0.1967 mol) of p-hydroxybenzaldehyde, along with 4.75 g of sodium metabisulfite dissolved in ethanol, were added to a reaction vessel. The mixture was heated to 80 °C under a nitrogen atmosphere and maintained for 24 h, then cooled to room temperature. After filtration to remove insoluble solids, the clear solution was poured into deionized water. Finally, the solution was filtered with deionized water and washed five times. After complete drying, the DBIM monomer shown in formula (V) was obtained.

[0103] Preparation of the main chain: 5.08 g (20 mmol) of 4,4'-difluorodiphenyl sulfone, 0.832 g (2 mmol) of PPH-3 monomer, 10.24 g (16 mmol) of PPH-4 monomer, and 1.266 g (2 mmol) of DBIM monomer were added to a 250 mL three-necked round-bottom flask equipped with a water separator. 80 mL of NMP was used as the solvent, and 5.5 g (40 mmol) of K₂CO₃ and 60 mL of toluene were added as the catalyst and water-carrying agent, respectively. The reaction was carried out at 135 °C for 6 h under N₂ atmosphere, followed by a reaction at 165 °C for 12 h. After the solution cooled to room temperature, it was poured into 300 mL of ethanol and flocculated under high-speed stirring to obtain a precipitate. After filtration, a yellow solid was obtained, which was repeatedly washed with ethanol and water, and then dried under vacuum at 80 °C for 24 h to obtain 17.42 g of polyarylene ether sulfone main chain polymer.

[0104] Preparation of anion exchange membrane: 5 g of polyarylether sulfone polymer was weighed into a round-bottom three-necked flask and dissolved in 30 mL of NMP solvent. The solution was magnetically stirred at 80 °C until completely dissolved. Then, 0.962 g of 1-bromopropane was added and stirred to obtain a casting solution. The casting solution was degassed and then poured into a clean glass mold. The mold was dried at 70 °C for 24 h to form a membrane, thus obtaining a polyarylether sulfone-based anion exchange membrane.

[0105] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0106] Example 8

[0107] Monomer preparation: The same preparation process as in Example 7 was used.

[0108] Main chain preparation: The same preparation process as in Example 7 was used.

[0109] Preparation of anion exchange membrane: The same preparation process as in Example 7 was used, except that 1.18 g of 1-bromopentane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0110] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0111] Example 9

[0112] Monomer preparation: The same preparation process as in Example 7 was used.

[0113] Main chain preparation: The same preparation process as in Example 7 was used.

[0114] Preparation of anion exchange membrane: The same preparation process as in Example 7 was used, except that 1.40 g of 1-bromopentane was added. After reaction and drying, polyarylether sulfone anion exchange membrane was obtained.

[0115] The thickness, ion exchange capacity, tensile strength, and swelling ratio of the prepared monovalent anion-selective anion exchange membrane were experimentally tested using national standard methods. The sheet resistance, transport number, permeation selectivity, and ion flux of the ion exchange membrane were tested using a self-made device. The results are shown in Table 1. (For specific test methods, please refer to the literature reports: Journal of Membrane Science 574(2019)181–195; Journal of Membrane Science 577(2019)153–164).

[0116]

[0117] Table 1.

Claims

1. A method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane, comprising the following steps: Step (1) Preparation of monomer (I): PPH-1, as shown in formula (I), was prepared by reacting n-propylamine with 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) under a nitrogen atmosphere and at 160 °C via reflux. Step (2) Preparation of monomer (II): PPH-2 of formula (II) was prepared by reacting pentamidine with 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) under a nitrogen atmosphere and at 170 °C via reflux. Step (3) Preparation of monomer (III): Heptamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) were reacted under a nitrogen atmosphere and refluxed at 180 °C to prepare PPH-3 as shown in formula (III); Step (4) Preparation of monomer (IV): 1-(3-aminopropyl)imidazolium and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) were reacted under a nitrogen atmosphere and refluxed at 195 °C to prepare PPH-4 as shown in formula (IV). Step (5) Preparation of monomer (V): 3,3'-Diaminobenzidine, p-hydroxybenzaldehyde, and sodium metabisulfite were reacted under a nitrogen atmosphere at 80°C to prepare DBIM as shown in formula (V); Step (6) Preparation of the main structural chain: PPH-1 monomer of formula (I), PPH-2 monomer of formula (II), PPH-3 monomer of formula (III), 4,4'-difluorodiphenyl sulfone monomer, PPH-4 monomer of formula (V), and DBIM monomer are added respectively, and then subjected to solvent co-condensation to obtain polyarylene ether sulfone with an amino-phenolphthalein structure in the main chain, as shown in formula (VI); wherein, The total molar ratio of PPH-1, PPH-2, PPH-3, PPH-4, and DBIM to the molar ratio of 4,4'-difluorodiphenyl sulfone is 1:1; the molar percentages of PPH-1, PPH-2, PPH-3, PPH-4, and DBIM are x:y:100-xy = 100%–70%:70%–40%:0%–40%; the number-average molecular weight of the polyarylene ether sulfone is Mn = 50,000–120,000. Where R1 is one of the above structural formulas; Step (7) Alkyl functionalization of the main structural chain and preparation of anion exchange membrane: The product (VI) prepared in step (6) is dissolved in an organic solvent, and then one of 1-bromopropane (VIII), 1-bromopentane (IX), and 1-bromoheptane (X) is added at a ratio of 1:2 and stirred for a certain period of time. After standing and degassing, a casting solution is obtained. The mass volume concentration of polyarylene ether sulfone in the casting solution is 3-8%. The organic solvent is one or more of DMF, DMAc, and NMP. The obtained casting solution is poured onto a glass plate and kept at 40-200℃ for 12-96 hours to achieve in-situ reaction and drying. After cooling, the film is peeled off from the glass plate in water to obtain an alkyl-functionalized anion exchange membrane with the structural formula shown in formula (VII) and a thickness of 70-150 μm. R2 is one of the above structural formulas, where x:y:100-xy=100%~70%:70%~40%:0%~40%.

2. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (1) is carried out as follows: In a reaction vessel, n-propylamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 30-80°C for 24-48 hours to obtain the PPH-1 monomer shown in formula (I). The molar ratio of n-propylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:

1. The dilute hydrochloric acid solution is a 0.1-0.5 mol / L aqueous hydrochloric acid solution.

3. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (2) is carried out as follows: In a reaction vessel, pentylamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 30-80°C for 24-48 hours to obtain the PPH-2 monomer shown in formula (II). The molar ratio of pentylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:

1. The dilute hydrochloric acid solution is a 0.1-0.5 mol / L aqueous hydrochloric acid solution.

4. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (3) is carried out as follows: In a reaction vessel, heptamine and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into an ice-water mixture. Then, dilute hydrochloric acid is added dropwise, and a white precipitate appears. The precipitate is washed with water 3-5 times and dried under vacuum at 30-80°C for 48 hours to obtain the PPH-3 monomer shown in formula (III). The molar ratio of pentanamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:

1. The dilute hydrochloric acid solution is a 0.1-0.5 mol / L hydrochloric acid aqueous solution.

5. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (4) is carried out as follows: In a reaction vessel, 1-(3-aminopropyl)imidazolium and 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature and slowly poured into deionized water. A precipitate is formed. The precipitate is then filtered and recrystallized from the solution. The precipitate is dried under vacuum at 40°C for 48 hours to obtain the PPH-4 monomer shown in formula (IV). The molar ratio of pentylamine to 3,3-bis(4-hydroxyphenyl)-3H-isobenzofuranone (phenolphthalein) is 1.5-2.5:

1.

6. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (5) is carried out as follows: In a reaction vessel, 3,3'-diaminobenzidine and p-hydroxybenzaldehyde are heated to reflux under a nitrogen atmosphere and maintained for 12-48 hours. Then, the mixture is cooled to room temperature, the insoluble solids are filtered off, the solution is poured into deionized water, washed 3-5 times with deionized water, and the precipitate is vacuum dried at 30-80°C for 24-48 hours to obtain the DBIM monomer shown in formula (V). The molar ratio of 3,3'-diaminobenzidine to p-hydroxybenzaldehyde is 1:2-4.

7. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: Step (6) is specifically implemented as follows: 4,4'-difluorodiphenyl sulfone is added to the reaction vessel, along with PPH-1, PPH-2 or PPH-3 as shown in formulas (I), (II), and (III) and PPH-4 as shown in formula (IV), DBIM as shown in formula (V), polar aprotic solvent B, salt-forming agent potassium carbonate, and dehydrating agent. The mixture is stirred and reacted at 100–180°C for 4–24 h under nitrogen protection. After the reaction is completed, the mixture is separated and dried to obtain the main chain polyarylene ether sulfone. The polar aprotic solvent B is at least one of N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone. The mass amount of the salt-forming agent potassium carbonate is 5.0–6.5 g / 20 mmol based on the amount of 4,4'-difluorodiphenyl sulfone. The dehydrating agent is toluene, and the volume ratio of toluene to polar aprotic solvent B is 0.2–0.7:

1.

8. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: In step (7), the molar ratio of polyarylether sulfone to one of 1-bromopropane, 1-bromopentane, and 1-bromoheptane is 0.4 to 1.00:

1.

9. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: In step (7), the mass-volume concentration of polyarylether sulfone in the casting solution is 5%.

10. The method for preparing a high-throughput, monovalent selective, double-sided chain anion exchange membrane according to claim 1, characterized in that: In step (7), the reaction conditions are: reaction at 70℃ for 18-36 h.

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