Hollow nanostructure enhanced ion exchange membrane and preparation method thereof

Abstract

The invention discloses a hollow nanostructure enhanced ion exchange membrane and a preparation method thereof, the ion exchange membrane is formed by compounding polymer resin and a hollow nanostructure, and the hollow nanostructure is obtained by polymerizing a precursor rich in terminal alkyne under the action of a template and removing the template after polymerization. And dispersing the hollow nanostructure in a polymer resin solution, casting the membrane-making solution into a membrane-making mold, and carrying out heat treatment to remove the solvent so as to form the membrane material. The preparation method is mild in synthesis condition and simple in process, large-scale preparation can be achieved, the hollow nanostructure can increase the water content of the membrane, swelling of the membrane is reduced in the application process of the membrane, the ionic conductivity of the membrane is improved, the membrane has high ionic conductivity, high mechanical strength, low swelling performance and low gas permeability, and the preparation method is suitable for industrial production. The method can be applied to application systems requiring rapid ion conduction, such as hydrogen-oxygen fuel cells, direct alcohol fuel cells, electrolyzed water, flow cells, chlor-alkali industry, water treatment and other fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ion exchange membranes, and more particularly to a hollow nanostructure-enhanced ion exchange membrane and a preparation method thereof. BACKGROUND

[0002] Ion exchange membranes, including anion exchange membranes and cation exchange membranes, are key materials for devices such as green hydrogen production by water electrolysis, green hydrogen application by fuel cells, water treatment, flow batteries, chlor-alkali industry, and high-value reduction of carbon dioxide. Ion exchange membranes with high stability, high ion conductivity, and low active substance permeation can improve the power performance, energy efficiency, and service life of devices, and reduce equipment costs. Currently, ion exchange membranes still face problems such as poor membrane stability, severe swelling, severe active substance permeation, and insufficient ion conductivity, and new concepts need to be developed to solve these problems.

[0003] Developing thin films is the main method to improve the ion conductivity of membranes, but thin films face problems such as high difficulty in processing and preparation, poor mechanical stability, severe active substance permeation, and insufficient service life. For example, in fuel cells and water electrolysis systems, ultra-thin ion exchange membranes cannot solve the problem of hydrogen cross-permeation, which seriously affects the safety of device use; for flow battery systems, cross-permeation of active ions affects the energy use efficiency and service life of the device.

[0004] By means of hollow structure to enhance the ion exchange membrane, the ion exchange degree of the ion exchange resin can be unchanged, the water content of the membrane can be significantly increased, the cost of the ion exchange resin can be reduced, the ion conductivity can be improved, the swelling rate of the membrane can be reduced, and the stability of the membrane can be improved. At the same time, the mechanical stability of the ion exchange membrane is improved by means of the mechanical stability of the hollow structure. The obtained hollow structure-enhanced ion exchange membrane has better mechanical properties and active substance permeation inhibition effect, and can develop ion exchange membrane materials with better mechanical properties, lower swelling, stronger ion conductivity, lower active substance permeation, and easier processing. SUMMARY

[0005] Therefore, the present application provides a hollow nanostructure-enhanced ion exchange membrane and a preparation method thereof, aiming to reduce the swelling rate of the membrane, increase the water content of the membrane, improve the mechanical stability of the membrane, inhibit the cross-permeation of active substances of the membrane, and obtain ion exchange membrane materials with low cost, high power, high efficiency, and high stability.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] Firstly, the present application provides a preparation method of a hollow nanostructure-enhanced ion exchange membrane, comprising the following steps:

[0008] (1) carrying out acetylene-acetylene coupling reaction under the action of sacrificial template agent with rich end acetylene precursor, removing the sacrificial template agent to obtain hollow nano-structured powder;

[0009] (2) stirring uniformly ion exchange resin and hollow nano-structured powder in solvent according to proportion to obtain casting solution;

[0010] (3) casting the casting solution of step (2) into mold, removing solvent by heat treatment to obtain hollow nano-structured reinforced ion exchange membrane material.

[0011] Preferably, the rich end acetylene precursor structure in step (1) is as follows:

[0012] ;

[0013] Wherein, A is end acetylene bond, n≥1, preferably greater than 2; B is aromatic ring or amine; C is one or more of sulfonate, phosphate, ammonium, m≥1.

[0014] Further, the rich end acetylene precursor is selected from one or more of the following structures:

[0015] , , , , , , , , , , .

[0016] Preferably, the sacrificial template agent is one or more of copper nanoparticles, copper sulfate nanoparticles, copper acetate nanoparticles, copper hydroxide nanoparticles, the particle size of the sacrificial template agent is 20nm-1µm, preferably 200-200nm.

[0017] Preferably, the acetylene-acetylene coupling reaction solvent in step (1) is a combination of at least one of pyridine, triethylamine, diisopropylamine, tetramethyl ethylenediamine nitrogen-containing alkaline solvent and at least one of toluene, dichloromethane, trichloromethane, ethyl acetate, N,N-dimethylformamide solvent;

[0018] The volume of nitrogen-containing alkaline solvent is not less than 5%, preferably 10%-20% by volume;

[0019] The mass ratio of sacrificial template agent to rich end acetylene precursor is (10-30):(0.3-4); the reaction temperature is 25-120℃, preferably 30-60℃, and the reaction time is <48h.

[0020] Preferably, the hydrochloric acid or sulfuric acid aqueous solution is used to remove the sacrificial template in step (1).

[0021] Preferably, the ion exchange resin in step (2) is one or a combination of the following structures

[0022] 、 、 、 、 、 、 、 .

[0023] Preferably, the hollow nanostructure powder in step (2) is 1%-60% of the mass of the ion exchange resin, preferably 5%-20%, and the solvent is a mixture of one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methyl pyrrolidone and water, with no volume limit.

[0024] Preferably, the heat treatment temperature in step (3) is 50-120°C, preferably 60-80°C, and the treatment time is <12h, preferably 30min-2h.

[0025] In addition, the present application also provides a hollow nanostructure enhanced ion exchange membrane prepared by the method described in the above technical solution.

[0026] As can be seen from the above technical solution, compared with the prior art, the present application provides a hollow nanostructure enhanced ion exchange membrane and a preparation method thereof, which has the following beneficial effects:

[0027] The present application improves the water content of the ion exchange membrane by means of the water storage function of the hollow nanostructure, reduces the swelling rate of the membrane, shortens the transmission distance of ions in the resin phase, and improves the transmission rate of ions, and improves the mechanical properties of the membrane by means of the mechanical properties of the hollow nanostructure.

[0028] The hollow nanostructure enhanced ion exchange membrane obtained by the present application can be prepared on a large scale, the preparation conditions are mild, the process is simple, and it can be applied to various scenes. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor.

[0030] Figure 1This is a cross-sectional morphology diagram of the hollow nanostructure-enhanced ion exchange membrane prepared in Example 2 of the present invention;

[0031] Figure 2 This is a cross-sectional morphology diagram of the hollow nanostructure-enhanced ion exchange membrane prepared in Example 3 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] (1) Add 10 g of 50 nm copper nanoparticles to the terminal-rich yne precursor. (0.5g) and (2g) was added to 400mL of tetramethylethylenediamine / N,N-dimethylformamide (volume ratio 1:10) solution and reacted at 90℃ for 7h. After the reaction was stopped, the insoluble matter was obtained by filtration. After drying, the insoluble matter was added to a 3% hydrochloric acid aqueous solution to remove copper nanoparticles. After centrifugation, washing and drying, hollow nanostructure powder was obtained.

[0035] (2) Mix 100 mg of the obtained hollow nanostructure powder with 500 mg Disperse the solution in 10 mL of dimethyl sulfoxide solvent and stir until homogeneous to obtain the casting solution;

[0036] (3) The casting liquid obtained in step (2) is cast into the film forming mold and dried at 80°C to remove the solvent for 1 hour to obtain the film material.

[0037] Comparative Example 1

[0038] Preparation of membrane materials without adding hollow nanostructure powder:

[0039] 500mg The casting solution dispersed in 10 mL of dimethyl sulfoxide solvent was cast into a film-forming mold, dried at 80°C to remove the solvent, and dried for 1 hour to obtain the membrane material.

[0040] Compared with Comparative Example 1, Example 1 showed that the swelling of the membrane was reduced by 5%, the water absorption rate of the membrane was the same, the mechanical strength of the membrane increased by 20% to 40 MPa, and the proton conductivity increased by 15%.

[0041] Example 2

[0042] (1) Add 5g of copper hydroxide nanoparticles with a particle size of 20nm to the terminal-rich yne precursor. (100mg) and 100 mg of copper hydroxide nanoparticles were added to 300 mL of pyridine / dichloromethane solution (volume ratio 1:5) and reacted at 40 °C for 10 h. After the reaction was stopped, the insoluble matter was obtained by filtration. After drying, the insoluble matter was added to a 2% sulfuric acid aqueous solution to remove copper hydroxide nanoparticles. After centrifugation, washing and drying, hollow nanostructured powder was obtained.

[0043] (2) Mix 100 mg of the obtained hollow nanostructured powder with 600 mg of Disperse the solution in 15 mL of N,N-dimethylformamide and stir until homogeneous to obtain the casting solution;

[0044] (3) The casting liquid obtained in step (2) is cast into the film forming mold and dried at 60°C to remove the solvent for 3 hours to obtain the film material.

[0045] Figure 1 The image shows a cross-sectional area scanning electron microscope image of the hollow structure-enhanced ion exchange membrane prepared in this embodiment. The membrane contains a large number of hollow structures, which can increase the water retention capacity of the membrane, improve the mechanical strength of the membrane, and reduce the swelling of the membrane.

[0046] Comparative Example 2

[0047] 100 mg of the obtained hollow nanostructure powder was mixed with 600 mg The solution was dispersed in 15 mL of N,N-dimethylformamide and stirred until homogeneous to obtain a casting solution. The solution was then cast into a film-forming mold and dried at 60 °C for 3 hours to remove the solvent, thus obtaining the membrane material.

[0048] Compared with the membrane material prepared in Comparative Example 2, the water absorption rate of the membrane in Example 2 increased by 20%, but the swelling of the membrane remained unchanged. The mechanical strength of the membrane increased by 30%, reaching 35 MPa, and the proton conductivity increased by 20%.

[0049] Example 3

[0050] (1) Add 10 g of copper acetate nanoparticles with a particle size of 500 nm to the terminal-rich alkyne precursor. (100mg) and (200 mg) was added to 500 mL of diisopropylamine / toluene (volume ratio 1:1) solution and reacted at 70 °C for 5 h. After the reaction was stopped, the insoluble matter was obtained by filtration. After drying, the insoluble matter was added to an aqueous solution of 1% hydrochloric acid to remove copper acetate nanoparticles. After centrifugation, washing and drying, hollow nanostructured powder was obtained.

[0051] (2) Mix 200 mg of the obtained hollow nanostructured powder with 1500 mg of Disperse the solution in 20 mL of N-methylpyrrolidone and stir until homogeneous to obtain the casting solution;

[0052] (3) The casting liquid obtained in step (2) is cast into the film forming mold and dried at 70°C to remove the solvent for 2 hours to obtain the film material.

[0053] Figure 2 The cross-sectional area scanning electron microscope image of the hollow structure-enhanced ion exchange membrane prepared for this embodiment clearly shows that the membrane contains a large number of hollow structures, indicating that the designed structure was successfully obtained. The hollow structure can increase the water retention capacity of the membrane and improve the ion transport rate of the membrane.

[0054] Comparative Example 3

[0055] 200 mg of the obtained hollow nanostructure powder was mixed with 1500 mg The solution was dispersed in 20 mL of N-methylpyrrolidone and stirred until homogeneous to obtain a casting solution. The solution was then poured into a film-forming mold and dried at 70 °C for 2 hours to remove the solvent, thus obtaining the membrane material.

[0056] Compared with the membrane material prepared in Comparative Example 3, the water absorption rate of the membrane in Example 3 increased by 30%, the swelling decreased by 5%, the mechanical strength of the membrane increased by 30% to 50 MPa, and the proton conductivity increased by 15%.

[0057] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a hollow nanostructure-reinforced ion exchange membrane, characterized in that, Includes the following steps: (1) The alkynyl coupling reaction was carried out with the terminal alkynyl precursor under the action of the sacrificial template agent, and the sacrificial template agent was removed to obtain hollow nanostructure powder. (2) Dissolve the ion exchange resin and hollow nanostructure powder in a solvent in a certain proportion and stir evenly to obtain the casting solution; (3) The casting liquid from step (2) is poured into a mold and heat-treated to remove the solvent to obtain a hollow nanostructure-enhanced ion exchange membrane material.

2. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The structure of the terminal-rich alkyne precursor described in step (1) is as follows: ； Wherein, A is a terminal alkyne bond, n≥1; B is an aromatic ring or amine; C is one or more of sulfonate, phosphate, and ammonium functional groups, m≥1.

3. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 2, characterized in that, The terminal-rich alkyne precursor is selected from one or more of the following structures: 、 、 、 、 、 、 、 、 、 、 。 4. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The sacrificial template agent is one or more of copper nanoparticles, copper sulfate nanoparticles, copper acetate nanoparticles, and copper hydroxide nanoparticles, and the particle size of the sacrificial template agent is 20 nm-1 µm.

5. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The solvent for the acetylene coupling reaction mentioned in step (1) is specifically a combination of at least one of the nitrogen-containing basic solvents selected from pyridine, triethylamine, diisopropylamine, and tetramethylethylenediamine, and at least one of the solvents selected from toluene, dichloromethane, chloroform, ethyl acetate, and N,N-dimethylformamide. The mass ratio of the sacrificial template agent to the terminal alkyne precursor is (10-30):(0.3-4); the reaction temperature is 25-120℃, and the reaction time is <48h.

6. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, In step (1), hydrochloric acid or sulfuric acid aqueous solution is used to remove the sacrificial template agent.

7. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The ion exchange resin mentioned in step (2) is one or a combination of the following structures. 、 、 、 、 、 、 、 。 8. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The hollow nanostructure powder mentioned in step (2) is 1%-60% of the mass of the ion exchange resin, and the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone and water.

9. The method for preparing a hollow nanostructure-reinforced ion exchange membrane according to claim 1, characterized in that, The heat treatment temperature in step (3) is 50℃-120℃, and the treatment time is <12h.

10. A hollow nanostructure-enhanced ion exchange membrane prepared by the method of any one of claims 1-9.

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