Anion exchange polymer, preparation method thereof and preparation method of anion exchange membrane

Abstract

The invention provides an anion exchange polymer, a preparation method thereof and a preparation method of an anion exchange membrane. The anion exchange polymer comprises a structural unit as shown in a formula (1) and / or a formula (2). According to the invention, the grafting rate of the quaternization reagent in the anion exchange polymer can be better controlled.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to an anion exchange polymer and a preparation method thereof, and a preparation method of an anion exchange membrane. Background Art

[0002] Hydrogen production from water electrolysis and fuel cell technologies are developing rapidly. It is foreseeable that they will become key technologies to support the development of new energy and build a synergistic pattern of hydrogen and electricity in the future. Taking hydrogen production from water electrolysis as an example, anion exchange membrane water electrolysis technology (AEM-WE) has the characteristics of zero gap and low cost, and is one of the most promising technologies for realizing the hydrogen economy. Among them, the anion exchange membrane (AEM) is the main component of AEM-WE, and its role is to convert OH - It conducts from the cathode to the anode, while blocking the direct transfer of gases and electrons between the electrodes.

[0003] In the related art, the preparation method of anion exchange polymers is to react aromatic monomers with ketones by means of a superacid-catalyzed Friedel-Crafts alkylation reaction, and then the obtained polycondensation polymer is subjected to a quaternization reaction with a functionalizing agent. This method has many shortcomings in industrial synthesis, mainly reflected in the poor controllability of the grafting rate. Summary of the invention

[0004] The embodiments of the present invention provide an anion exchange polymer and a preparation method thereof and a preparation method of an anion exchange membrane, which can improve the technical problem of poor controllability of grafting rate of existing anion exchange polymers.

[0005] In a second aspect, an embodiment of the present invention provides an anion exchange polymer, comprising a structural unit represented by formula (1) and / or formula (2),

[0006]

[0007]

[0008] Wherein, A in formula (1) and formula (2) independently comprises

[0009]

[0010] One or more of the following, where R 1 , R 2 and R are independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring;

[0011] A r1 and A r2 It is a phenyl-containing monomer.

[0012] In one embodiment, A r1 include

[0013]

[0014] One or more of; and / or

[0015] A r2 include

[0016]

[0017] One or more of; and / or

[0018] The anion exchange polymer also includes one or more of trifluoroacetate ion, p-toluenesulfonate ion, iodide ion, bromide ion, methanesulfonate ion, ethanesulfonate ion, but-3-yn-1-ylmethanesulfonate ion, allylsulfonate ion, benzenesulfonate ion, nitrobenzenesulfonate ion, trifluoromethanesulfonate ion, trifluoromethanesulfonate ion, toluenesulfonate ion, toluene-4-sulfonate ion, toluenesulfonate ion, neopentylbenzenesulfonate ion, tetrahydro-2H-pyran-4-ylmethanesulfonate ion and p-toluenesulfonate ion; and / or

[0019] The structural formula of anion exchange polymer is

[0020]

[0021] Among them, the ratio of X to Y is (85-95):(5-15).

[0022] In a second aspect, an embodiment of the present invention provides a method for preparing an anion exchange polymer, comprising the following steps:

[0023] Providing a nitrogen-containing heterocyclic ketone compound and a quaternizing agent, and subjecting the nitrogen-containing heterocyclic ketone compound and the quaternizing agent to a quaternizing reaction to obtain a quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound;

[0024] Providing a monomer containing phenyl and a strong acid catalyst, mixing a quaternary ammonium salt ionic liquid of a nitrogen-containing heterocyclic ketone compound with the monomer containing phenyl and the strong acid catalyst, so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl undergo a polymerization reaction to obtain an initial reaction product;

[0025] After the initial reaction product is subjected to a second drying, an anion exchange polymer is obtained.

[0026] In one embodiment, the nitrogen-containing heterocyclic ketone compound comprises

[0027]

[0028] One or more of the following, where R 1 , R 2and R are independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring; and / or

[0029] The quaternizing agent includes one or more of methyl trifluoroacetate, methyl p-toluenesulfonate, iodomethane, propyl bromide, ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, ethyl bromide, butyl bromide, pentyl bromide, hexyl bromide, cyclohexyl bromide, cyclopentyl bromide, cyclohexyl bromide, methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate, ethyl ethanesulfonate, but-3-yn-1-yl methanesulfonate, allyl allyl sulfonate, methyl benzenesulfonate, methyl nitrobenzenesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, ethyl toluenesulfonate, toluene-4-sulfonic acid cyclobutyl ester, butyl toluenesulfonate, neopentylbenzenesulfonate, tetrahydro-2H-pyran-4-yl methanesulfonate and cyclohexyl p-toluenesulfonate; and / or

[0030] Monomers containing phenyl groups include

[0031]

[0032] One or more of;

[0033] The strong acid catalyst includes one or more of trifluoromethanesulfonic acid, pentafluoropropionic acid, trifluoroacetic acid, trifluoromethanesulfonic acid and heptafluorobutyric acid.

[0034] In one embodiment, the molar ratio of the nitrogen-containing heterocyclic ketone compound to the quaternizing agent is 10:(8-12); and / or

[0035] The molar ratio of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound, the monomer containing phenyl and the strong acid catalyst is (1-2):1:(4-8); and / or

[0036] The weight average molecular weight of the anion exchange polymer is 40000 g / mol-500000 g / mol.

[0037] In one embodiment, the nitrogen-containing heterocyclic ketone compound and the quaternizing agent are subjected to a quaternization reaction, comprising: providing a first solvent, mixing the nitrogen-containing heterocyclic ketone compound in the first solvent, and then adding the quaternizing agent to carry out a quaternization reaction; and / or

[0038] The temperature of the quaternization reaction is 10°C-100°C, and the time of the quaternization reaction is 1h-36h; and / or

[0039] The quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound is mixed with a monomer containing a phenyl group and a strong acid catalyst, so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing a phenyl group undergo a polymerization reaction, comprising: mixing the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound with the monomer containing a phenyl group, and then adding a strong acid catalyst to undergo a polymerization reaction; and / or

[0040] The temperature when the strong acid catalyst is added is -5°C to 0°C; and / or

[0041] The polymerization reaction temperature is 0°C-24°C, and the polymerization reaction time is 1h-15h.

[0042] In one embodiment, after the quaternization reaction, the method further comprises: performing a first washing, filtering, and a first drying on the product of the quaternization reaction.

[0043] In one embodiment, the reagent used in the first washing comprises one or more of ethanol, ethyl acetate, ethylene glycol, ether, tetrahydrofuran, acetone and water; and / or

[0044] In some embodiments, the first drying temperature is 60° C.-100° C., and the first drying time is 8 h-12 h.

[0045] In one embodiment, the precipitation treatment includes: placing the initial reaction product in water and precipitating a crude anion exchange polymer;

[0046] The method further comprises: performing a second washing on the product obtained by the precipitation treatment, and then performing a second drying.

[0047] In one embodiment, the detergent used in the second washing comprises one or more of water and an inorganic salt solution; and / or

[0048] The temperature of the second drying is 60°C-100°C, and the time of the second drying is 22h-26h.

[0049] In a third aspect, an embodiment of the present invention provides a method for preparing an anion exchange membrane, comprising the following steps:

[0050] A second solvent and an anion exchange polymer according to any one of claims 1 to 8 are provided, the anion exchange polymer is dissolved in the second solvent, and then subjected to membrane forming treatment to obtain an anion exchange membrane.

[0051] In some embodiments, the second solvent comprises one or more of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and acetonitrile; and / or

[0052] In some embodiments, the solid content of the solution obtained by dissolving the anion exchange polymer in the second solvent is 17 wt % to 20 wt %.

[0053] In some embodiments, the film forming process includes: forming a wet film, and then performing a first drying; and / or

[0054] Before the membrane forming treatment, the method further comprises: filtering a solution obtained by dissolving the anion exchange polymer in the second solvent, using a filter having a pore size of 2000-6000 meshes.

[0055] In an embodiment of the present invention, by first reacting a quaternary ammonium agent with a nitrogen-containing heterocyclic ketone compound to form a quaternary ammonium salt ionic liquid and then performing a polymerization reaction, the grafting rate of the quaternary ammonium agent in the anion exchange polymer can be better controlled compared to directly reacting the quaternary ammonium agent with a polymer formed by a nitrogen-containing heterocyclic ketone compound and a phenyl-containing monomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 It is a polymerization pathway diagram of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl group provided in Examples 1 and 2 of the present application;

[0058] Figure 2 It is a polymerization pathway diagram of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl group provided in Examples 3 and 4 of the present application;

[0059] Figure 3 It is a polymerization pathway diagram of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl group provided in Examples 5 and 6 of the present application;

[0060] Figure 4 It is a polymerization pathway diagram of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl group provided in Examples 7 and 8 of the present application;

[0061] Figure 5 It is a synthetic route diagram of the preparation method of anion exchange polymer provided in Comparative Example 1 of the present application;

[0062] Figure 6 It is a synthetic route diagram of the preparation method of anion exchange polymer provided in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device.

[0064] The technical solution of this application is as follows:

[0065] In a first aspect, an embodiment of the present invention provides an anion exchange polymer, comprising a structural unit represented by formula (1) and / or formula (2),

[0066]

[0067] Wherein, A in formula (1) and formula (2) independently comprises

[0068]

[0069] One or more of the following, where R 1 , R 2 and R are independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring;

[0070] A r1 and A r2 It is a phenyl-containing monomer.

[0071] In one embodiment, A r1 include

[0072]

[0073] One or more of; and / or

[0074] A r2 include

[0075]

[0076] One or more of; and / or

[0077] The anion exchange polymer also includes one or more of trifluoroacetate ion, p-toluenesulfonate ion, iodide ion, bromide ion, methanesulfonate ion, ethanesulfonate ion, but-3-yn-1-ylmethanesulfonate ion, allylsulfonate ion, benzenesulfonate ion, nitrobenzenesulfonate ion, trifluoromethanesulfonate ion, trifluoromethanesulfonate ion, toluenesulfonate ion, toluene-4-sulfonate ion, toluenesulfonate ion, neopentylbenzenesulfonate ion, tetrahydro-2H-pyran-4-ylmethanesulfonate ion and p-toluenesulfonate ion; and / or

[0078] The structural formula of anion exchange polymer is

[0079]

[0080] Among them, the ratio of X to Y is (85-95):(5-15).

[0081] In a second aspect, the present invention provides a method for preparing an anion exchange polymer, comprising the following steps:

[0082] Providing a nitrogen-containing heterocyclic ketone compound and a quaternizing agent, and subjecting the nitrogen-containing heterocyclic ketone compound and the quaternizing agent to a quaternizing reaction to obtain a quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound;

[0083] Providing a monomer containing phenyl and a strong acid catalyst, mixing a quaternary ammonium salt ionic liquid of a nitrogen-containing heterocyclic ketone compound with the monomer containing phenyl and the strong acid catalyst, so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl undergo a polymerization reaction to obtain an initial reaction product;

[0084] The initial reaction product is subjected to precipitation treatment to obtain an anion exchange polymer.

[0085] In the present application, by first reacting a quaternary ammonium agent with a nitrogen-containing heterocyclic ketone compound to form a quaternary ammonium salt ionic liquid, and then performing a polymerization reaction, compared with directly reacting a quaternary ammonium agent with a nitrogen-containing heterocyclic ketone compound and a phenyl-containing monomer to form a polymer, the grafting controllability of the quaternary ammonium agent with the nitrogen-containing heterocyclic ketone compound is higher than the grafting controllability with the macromolecular polymer, so that the grafting rate of the quaternary ammonium agent in the anion exchange polymer can be better controlled, thereby making the obtained anion exchange polymer have low water absorption and swelling, excellent ionic conductivity and mechanical properties; at the same time, compared with using a phenyl-containing monomer The monomers of the nitrogen-containing heterocyclic ketone compounds are polymerized with the nitrogen-containing heterocyclic ketone compounds. The amount of strong acid catalyst required for the polymerization of the same dose of the phenyl-containing monomers is less, thereby reducing the amount of strong acid catalyst used; the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compounds is used as a reaction monomer to polymerize with the phenyl-containing monomers, and the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compounds can be used as a solvent, without the need to use an additional solvent, thereby replacing the toxic solvent required for the polymerization reaction of the phenyl-containing monomers and the nitrogen-containing heterocyclic ketone compounds, thereby achieving green synthesis, reducing the post-treatment process of the toxic solvent, and reducing the post-treatment cost.

[0086] In some embodiments, the anion exchange polymer is in the form of strips. In the present application, the product precipitated by the precipitation treatment is in the form of strips, and the cutting process step can be reduced during the application process. Compared with the anion exchange polymer obtained by polymerizing the nitrogen-containing heterocyclic ketone compound with the phenyl-containing monomer and then quaternizing it, it still needs to be cut. The preparation method of the present application can reduce the industrial production steps and costs.

[0087] In some embodiments, the initial reaction product is a viscous liquid.

[0088] In some embodiments, the phenyl-containing monomers include

[0089]

[0090] One or more of .

[0091] In some embodiments, R 1 and R 2 Each of the following is independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, cyclopropyl, trifluoromethyl, hydroxyl, pyridyl, phenyl, o-tolyl, m-tolyl, p-tolyl and mesityl; and R is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, isopropyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl, trifluoromethyl, hydroxyl and N,N,N-trimethylpentylammonium.

[0092] In some embodiments, the nitrogen-containing heterocyclic ketone compounds include

[0093]

[0094] One or more of the following, where R 1 , R 2 and R are each independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring.

[0095] In this application, by controlling R 1 , R 2 , R 3 The type of R and R can regulate the electronegativity of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound or change the steric hindrance of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound, thereby controlling the polymerization efficiency. The nitrogen-containing heterocyclic ketone compound can be a nitrogen-containing heterocyclic ketone compound in the form of a hydrochloride.

[0096] In some embodiments, the nitrogen-containing heterocyclic ketone compounds include

[0097]

[0098] In this way, the grafting rate of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the quaternary ammonium agent can be better controlled.

[0099] In some embodiments, the nitrogen-containing heterocyclic ketone compound and the quaternizing agent are subjected to a quaternization reaction, comprising: providing a first solvent, mixing the nitrogen-containing heterocyclic ketone compound in the first solvent, and then adding the quaternizing agent to carry out a quaternization reaction.

[0100] In some embodiments, the molar ratio of the nitrogen-containing heterocyclic ketone compound to the quaternary ammonium agent is 10:(8-12), for example, it can be 10:8, 10:8.5, 10:9, 10:9.5, 10:10, 10:10.5, 10:11, 10:11.5, 10:12, etc.

[0101] In some embodiments, the temperature of the quaternization reaction is 10°C-100°C, for example, it can be 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc., and the time of the quaternization reaction is 1h-36h, for example, it can be 1h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 36h, etc.

[0102] In some embodiments, the quaternizing agent includes one or more of methyl trifluoroacetate, methyl p-toluenesulfonate, iodomethane, propyl bromide, ethyl iodide, propyl iodide, butyl iodide, pentane iodide, hexane iodide, ethyl bromide, butyl bromide, pentane bromide, hexane bromide, cyclohexyl bromide, cyclopentane bromide, cyclohexyl bromide, methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate, ethyl ethanesulfonate, but-3-yn-1-yl methanesulfonate, allyl allylsulfonate, methyl benzenesulfonate, methyl nitrobenzenesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, ethyl toluenesulfonate, cyclobutyl toluene-4-sulfonate, butyl toluenesulfonate, neopentylbenzenesulfonate, tetrahydro-2H-pyran-4-yl methanesulfonate, and cyclohexyl p-toluenesulfonate.

[0103] In some embodiments, the first solvent includes one or more of ethyl acetate, dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, and acetonitrile.

[0104] In some embodiments, a quaternary ammonium salt ionic liquid of a nitrogen-containing heterocyclic ketone compound is mixed with a monomer containing a phenyl group and a strong acid catalyst, so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing a phenyl group undergo a polymerization reaction, comprising: mixing the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound with the monomer containing a phenyl group, and then adding a strong acid catalyst for polymerization reaction.

[0105] In some embodiments, the strong acid catalyst includes one or more of trifluoromethanesulfonic acid, pentafluoropropionic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, and heptafluorobutyric acid.

[0106] In some embodiments, the molar ratio of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound, the phenyl-containing monomer and the strong acid catalyst is (1-2):1:(4-8), for example, it can be 1:1:4, 1.2:1:5, 1.3:1:6, 1.5:1:7, 1.8:1:8, 2.0:1:8, etc.

[0107] In some embodiments, the temperature when the strong acid catalyst is added is -5°C to 0°C, for example, -5°C, -4°C, -3°C, -2°C, -1°C, 0°C, etc. When the strong acid is added, a large amount of heat is released. In this way, the temperature rise caused by the heat release of the strong acid can be reduced.

[0108] In some embodiments, the polymerization temperature is 0°C-24°C, for example, 0°C, 2°C, 4°C, 6°C, 8°C, 10°C, 12°C, 14°C, 16°C, 18°C, 20°C, 22°C, 24°C, etc., and the polymerization time is 1h-15h, for example, 1h, 3h, 4h, 7h, 9h, 11h, 13h, 15h, etc. In this way, the rate of the polymerization reaction can be accelerated.

[0109] In one embodiment, the precipitation treatment includes: placing the initial reaction product in water and precipitating the crude anion exchange polymer. Thus, by placing the initial reaction product in water, the crude anion exchange polymer can be precipitated.

[0110] In one embodiment, after the precipitation treatment, the method further comprises: performing a second washing on the product obtained by the precipitation treatment, and then performing a second drying.

[0111] In one embodiment, the second washing comprises washing the product obtained from the precipitation treatment to neutrality.

[0112] In some embodiments, the detergent used in the second washing includes one or more of water and an inorganic salt aqueous solution. In this way, the product in the initial reaction product can be separated, and at the same time, the inorganic salt can remove the acid carried in the initial reaction product.

[0113] In some embodiments, the inorganic salt aqueous solution includes one or more of an aqueous potassium carbonate solution, an aqueous sodium carbonate solution, an aqueous sodium chloride solution, an aqueous potassium hydroxide solution, and an aqueous calcium chloride solution.

[0114] In some embodiments, the second drying temperature is 60°C-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc., and the second drying time is 22h-26h, for example, it can be 22h, 23h, 24h, 25h, 26h, etc.

[0115] In some embodiments, the weight average molecular weight of the anion exchange polymer is 40,000-500,000 g / mol, for example, 40,000 g / mol, 100,000 g / mol, 150,000 g / mol, 200,000 g / mol, 250,000 g / mol, 300,000 g / mol, 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, etc.

[0116] In some embodiments, the weight average molecular weight of the anion exchange polymer is 40,000-250,000 g / mol, for example, 40,000 g / mol, 80,000 g / mol, 100,000 g / mol, 120,000 g / mol, 150,000 g / mol, 170,000 g / mol, 200,000 g / mol, 220,000 g / mol, 250,000 g / mol, etc.

[0117] First washing and first drying In some embodiments, after the quaternization reaction, the process further includes: first washing, filtering, and first drying the product of the quaternization reaction, so that impurities such as unreacted quaternization agent or ketone compound can be removed.

[0118] In some embodiments, the reagent used for the first washing includes one or more of ethanol, ethyl acetate, ethylene glycol, diethyl ether, tetrahydrofuran, acetone and water.

[0119] In some embodiments, the first drying temperature is 60°C-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc., and the first drying time is 8h-12h, for example, it can be 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, etc.

[0120] In a third aspect, an embodiment of the present application provides a method for preparing an anion exchange membrane, comprising the following steps:

[0121] Providing a second solvent and the anion exchange polymer, dissolving the anion exchange polymer in the second solvent, and then performing a membrane forming process to obtain an anion exchange membrane;

[0122] The anion exchange polymer is the anion exchange polymer described above.

[0123] In some embodiments, the second solvent includes one or more of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and acetonitrile.

[0124] In some embodiments, the solid content of the solution obtained by dissolving the anion exchange polymer in the second solvent is 17 wt % to 20 wt %. In this way, the thickness of the anion exchange membrane can be better controlled.

[0125] In some embodiments, before the membrane forming process, the method further comprises filtering the solution obtained by dissolving the anion exchange polymer in the second solvent.

[0126] In some embodiments, the pore size of the filter used for filtration is 2000-6000 mesh, for example, 2000 mesh, 3000 mesh, 4000 mesh, 5000 mesh, 6000 mesh, etc. In this way, the undissolved part and impurities in the anion exchange polymer can be removed.

[0127] In some embodiments, the film forming process includes: forming a wet film, and then performing a first drying.

[0128] In some embodiments, the first drying temperature is 40°C-80°C, for example, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc., and the first drying time is 8h-12h, for example, it can be 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, etc.

[0129] The following is a description with reference to specific embodiments.

[0130] Example 1

[0131] An anion exchange polymer and a preparation method thereof, comprising the following steps:

[0132] (1) N-methyl-4-piperidone (10 mol) and ethyl acetate (50 mL) were mixed at room temperature, and then iodomethane (8 mol) was added dropwise. After the addition was completed, the mixture was reacted for 2 h. After the reaction was completed, ethyl acetate was added for washing, and then the mixture was filtered and dried at 80° C. for 10 h to obtain a quaternary ammonium salt ionic liquid of a nitrogen-containing heterocyclic ketone compound;

[0133] (2) A quaternary ammonium salt ionic liquid of a nitrogen-containing heterocyclic ketone compound (0.36 mol) and p-terphenyl (0.3 mol) were added to a 500 mL three-necked flask. After mechanical stirring, 200 mL of trifluoromethanesulfonic acid and 10 mL of trifluoroacetic acid were added under ice bath conditions. The ice bath conditions were maintained during the reaction. After 24 hours of reaction, the solution became a viscous liquid. The viscous liquid was poured into water to precipitate a crude polymer, which was then washed with deionized water until neutral and dried at 80° C. for 24 hours to obtain an anion exchange polymer.

[0134] An anion exchange membrane and a preparation method thereof, comprising the following steps:

[0135] The anion exchange polymer was dissolved in dimethyl sulfoxide (DMSO) to obtain a homogeneous solution with a solid content of 17 wt%-20 wt%. The homogeneous solution was poured onto a coating machine and dried at 60° C. for 8 h to obtain an anion exchange membrane.

[0136] Example 2

[0137] This embodiment is substantially the same as embodiment 1, except that the amount of iodomethane used in this embodiment is 12 mol.

[0138] Example 3

[0139] This embodiment is substantially the same as embodiment 1, except that in this embodiment, N-methyl-4-piperidone is replaced by quinuclidinone hydrochloride.

[0140] Example 4

[0141] This embodiment is substantially the same as embodiment 2, except that the amount of iodomethane used in this embodiment is 12 mol.

[0142] Example 5

[0143] This embodiment is substantially the same as embodiment 1, except that in this embodiment, 0.3 mol of p-terphenyl is replaced by 0.3 mol of p-terphenyl and 0.003 mol of 1,3,5-triphenylbenzene.

[0144] Example 6

[0145] This embodiment is substantially the same as embodiment 2, except that in this embodiment, 0.3 mol of p-terphenyl is replaced by 0.3 mol of p-terphenyl and 0.003 mol of 1,3,5-triphenylbenzene.

[0146] Example 7

[0147] This embodiment is substantially the same as embodiment 3, except that in this embodiment, 0.3 mol of p-terphenyl is replaced by 0.3 mol of p-terphenyl and 0.003 mol of triphenylmethane.

[0148] Example 8

[0149] This embodiment is substantially the same as embodiment 4, except that in this embodiment, 0.3 mol of p-terphenyl is replaced by 0.3 mol of p-terphenyl and 0.003 mol of triphenylmethane.

[0150] Comparative Example 1

[0151] An anion exchange membrane and a preparation method thereof, comprising the following steps:

[0152] (1) 9.7 mol of p-terphenyl and 10 mol of N-methyl-4-piperidone were dissolved in 120 mL of dichloromethane, and stirred at 0° C., while 240 mL of trifluoromethanesulfonic acid and 22.8 mL of trifluoroacetic acid were added dropwise. After the addition was completed, stirring was continued for 72 hours to obtain a viscous liquid. The viscous liquid was washed with 1 L of pure water, 2 L of NaOH aqueous solution (concentration of 1 mol / L), and 1 L of pure water in sequence, and then dried at 100° C. for 30 hours to obtain 28.9 g of a nitrogen-containing heterocyclic polymer in the form of a light yellow powder;

[0153] (2) 10 mol of nitrogen-containing heterocyclic polymer and 20 mol of iodomethane were dissolved in 100 mL of dimethyl sulfoxide, and the mixture was stirred at 60° C. for 10 hours. After the reaction was completed, the obtained product was washed three times with 2 L of pure water and then dried at 100° C. for 30 hours to obtain 21.2 g of a pale yellow powdery quaternary ammonium salt polymer;

[0154] (3) taking 100 mg of quaternary ammonium salt polymer, dissolving it in 20 mL of N,N-dimethylacetamide to obtain a polymer solution, coating the polymer solution on a glass plate, drying it in an oven at 80° C. for 5 hours, and then heating it to 120° C. and drying it for another 20 hours to obtain an iodine ion exchange membrane;

[0155] (4) The iodine ion exchange membrane was immersed in a 1 M NaOH aqueous solution at room temperature for 5 hours, the membrane was taken out and washed with pure water, and then dried in an oven at 100° C. for 5 hours under nitrogen protection to obtain an alkaline anion exchange membrane.

[0156] Comparative Example 2:

[0157] An anion exchange membrane and a preparation method thereof, comprising the following steps:

[0158] (1) 9.7 mol of p-terphenyl, 0.2 mol of 1,3,5-triphenylbenzene and 10 mol of quinuclidinone hydrochloride were dissolved in 120 mL of dichloromethane, and stirred at 0° C., while 200 mL of trifluoromethanesulfonic acid and 10 mL of trifluoroacetic acid were added dropwise. After the addition was completed, stirring was continued for 72 hours to obtain a viscous liquid. The viscous liquid was washed with 1 L of pure water, 2 L of NaOH aqueous solution (with a concentration of 1 mol / L), and 1 L of pure water in sequence, and then dried at 100° C. for 30 hours to obtain 31.2 g of a nitrogen-containing heterocyclic polymer in the form of a light yellow powder;

[0159] (2) 10 mol of nitrogen-containing heterocyclic polymer and 20 mol of iodomethane were dissolved in 100 mL of dimethyl sulfoxide, and the mixture was stirred at 60° C. for 10 hours. After the reaction was completed, the obtained product was washed three times with 2 L of pure water and then dried at 100° C. for 30 hours to obtain 21.2 g of a pale yellow powdery quaternary ammonium salt polymer;

[0160] (3) 100 mg of quaternary ammonium salt polymer was dissolved in 20 mL of N,N-dimethylacetamide to obtain a polymer solution, the polymer solution was coated on a glass plate, dried in an oven at 80° C. for 5 hours, and then heated to 120° C. and dried for another 20 hours to obtain an iodine ion exchange membrane;

[0161] (4) The iodine ion exchange membrane was immersed in a 1 M NaOH aqueous solution at room temperature for 5 hours, the membrane was taken out and washed with pure water, and then dried in an oven at 100° C. for 5 hours under nitrogen protection to obtain an alkaline anion exchange membrane.

[0162] Comparative Example 3

[0163] This comparative example is substantially the same as Example 1, except that the amount of methyl iodide used in this comparative example is twice that of Example 2.

[0164] Test Example: The quaternary ammonium salt ionic liquid, anion exchange polymer and anion exchange membrane of the nitrogen-containing heterocyclic ketone compound obtained in the examples and comparative examples were subjected to performance tests. The test data are shown in Table 1.

[0165] 1. Mechanical properties test

[0166] Test method: Refer to GB T 20042.3

[0167] Measure the thickness and width of the sample under constant temperature and humidity conditions of 23℃±2℃ and 50%±10% relative humidity. Place the sample in the test fixture. When measuring the tensile strength and elongation at break, different tensile speeds can be used, selected within the range of 100mm / min. For each tensile speed, a separate specimen should be used. After the sample breaks, read the corresponding load value.

[0168] a. Tensile strength: The ratio of the maximum load that an anion exchange membrane can withstand when it breaks under pure tensile force to the width of the stretched membrane material. It is divided into transverse and longitudinal tensile strengths and is used to evaluate the mechanical strength of the membrane.

[0169] b. Elongation at break: The ratio of the distance between two points at break to the original length under the maximum load before the anion exchange membrane breaks. It is used to indicate the maximum deformation that the anion exchange membrane can withstand before breaking, and is used to indicate the flexibility of the membrane.

[0170] 2. Water absorption and swelling performance test

[0171] a: Cut the anion exchange membrane into 1cm*4cm size, put it into 1M KOH and change the alkali three times, and test the swelling performance in 80℃ deionized water;

[0172] b: Cut the anion exchange membrane into 5cm*5cm size, put it into 1M KOH and change the alkali three times, and test the water absorption performance in 80℃ deionized water.

[0173] 3.OH - Ionic conductivity performance

[0174] Cut 10mm×45mm anion exchange membrane as a sample. Put the sample into 1M KOH aqueous solution and exchange ions at 80℃ for 24h. After completion, wash it with deionized water until it is neutral and store it in deionized water. Before testing, use a thickness gauge and a ruler to measure the thickness and width of the anion exchange membrane respectively. Take the average value of three tests as the width a and thickness b. Take at least 3 points for each group of samples.

[0175] The ionic conductivity is tested by the four-electrode probe method using an ionic conductivity test device. First, lay the sample flat on the platinum wire electrode without wrinkles to ensure good contact between the sample and the platinum wire electrode, then gently place the cover and tighten the screws with a wrench. After tightening, the sample should have no protrusions, completing the assembly of the test module.

[0176] The test fixture is connected to the temperature and humidity control system. 2 (purity 99.999%, the same below) purge, the flow rate on both sides is set to 500sccm. The humidification condition is set to 100% RH, ensuring that the temperature of the pipeline is 5°C higher than the temperature of the test device; the actual test temperature is set according to demand. Then start the temperature and humidity device, and start the electrolysis process after reaching the set conditions, maintaining N 2 Purge, gas flow remains unchanged.

[0177] Electrolysis process: The membrane material to be tested is electrolyzed using the constant current method. The electrolysis current value can be adjusted within the electrolysis potential of 2V to meet the actual test needs. During the electrolysis process, the electrodes undergo an electrochemical reaction, causing the carbonate (bi) ions in the anion exchange membrane to convert to CO 2 The gas is discharged until all anions in the membrane are exchanged for OH in situ. - Whether the electrolysis has reached equilibrium is determined by the change in overpotential during the test process. Generally, when the overpotential fluctuation value is less than 1%, the electrolysis process is considered to be over and the system has reached equilibrium.

[0178] EIS test process: After electrolysis equilibrium, perform EIS test, select current perturbation mode, frequency range is 0.1Hz-1.0MHz, perturbation amplitude is 1mA, and obtain impedance spectrum. Read the impedance value R of the membrane sample from the intersection of the low-frequency part of the spectrum line and the real axis, and calculate the in-plane ionic conductivity of the sample according to the following formula:

[0179] σ=l / (a×b×R)

[0180] Where:

[0181] σ——is the in-plane ionic conductivity of the sample, in millisiemens per centimeter (mS / cm);

[0182] l——The distance between electrodes, in centimeters (cm);

[0183] a——the width of the film sample, in centimeters (cm);

[0184] b——the thickness of the film sample, in centimeters (cm);

[0185] R——is the measured impedance of the membrane sample, in ohms (Ω). 5. Polarization performance test: In the anode nickel ferrite-cathode platinum carbon catalyst system at 60℃@1M KOH, the polarization curve of the alkaline membrane single cell was tested.

[0186] 6.IEC determination: using chemical precipitation titration method, using AgNO 3 Titration of Cl - , K 2 CrO 4 As an indicator. First, soak the anion exchange membrane material in 1M KOH solution and exchange for 24 hours to obtain a hydroxide-type alkaline membrane. Then soak the alkaline membrane in 1M NaCl solution and exchange for 48 hours to obtain a chloride-type AEM. Wash the chloride-type AEM in deionized water to ensure that the NaCl adsorbed on the AEM is completely washed away. Then wipe the water on the surface of the chloride-type AEM with dust-free paper and soak it in 50mL0.2M NaNO 3 The purpose of the solution is to fully exchange the chloride ions in the AEM for NaNO 3 In solution. NaNO 3 The chloride ions exchanged in the solution are the anion content in the AEM that needs to be titrated. 3 Solution: Accurately weigh 0.58g of high-grade pure NaCl on an electronic balance with an accuracy of 0.01mg, dissolve it in deionized water, and prepare a 0.02M standard NaCl solution in a 500mL volumetric flask. Use a pipette to accurately measure 3.00mL of standard NaCl in a conical flask, add two drops of K 2 CrO 4 Indicator, 0.01M AgNO 3 Titrate the standard NaCl solution until a brick-red precipitate is produced and the titration endpoint is reached. Record the consumed AgNO 3 The volume of the solution was titrated 5 times in parallel, and the average value was taken to calculate the AgNO 3 The exact concentration of the solution. Titration of ion content in AEM: Take 10mL of NaNO that has been fully soaked in chlorine-type AEM. 3 The solution was placed in a conical flask and two drops of K 2 CrO 4 Indicator, use calibrated 0.01MAgNO 3 Titrate until a brick-red precipitate is produced and record the consumed AgNO 3 The volume of the solution was titrated three times in parallel, and the average value was taken to calculate the ion content in AEM. Finally, the AEM was fully washed with deionized water, dried, and weighed. The IEC calculation formula is as follows:

[0187]

[0188] in, AgNO 3 Solution concentration, To titrate the AgNO consumed by AME 3 The volume of the solution, m AEM is the dry mass of AME.

[0189] Table 1

[0190]

[0191]

[0192] From Table 1, we can see that:

[0193] Compared with Example 2, Example 3, Example 4, Example 5, Example 6, and Example 7, the anion exchange membranes of Example 1, Example 3, Example 5, and Example 7 have greater tensile strength, smaller elongation at break, smaller water absorption, smaller swelling rate, smaller conductivity, smaller ion exchange capacity (IEC), and greater polarization performance. The reason is that less quaternizing agent is used in Example 1, Example 3, Example 5, and Example 7, so that the grafting rate of the quaternizing agent in the anion exchange polymer is lower. It can be seen that the grafting rate of the quaternizing agent can be controlled by controlling the amount of the quaternizing agent.

[0194] Comparative Example 2 is compared with Comparative Example 3, and the quaternizing agent used in Comparative Example 3 is more, but the ion exchange capacity (IEC) of the two is the same. It can be seen that the preparation method of the comparative example, by adjusting the consumption of the quaternizing agent, can not reach the effect of controlling the grafting rate of the quaternizing agent in the anion exchange polymer. Embodiment 1 is compared with Embodiment 5, and Embodiment 2 is compared with Embodiment 6, and Embodiment 3 is compared with Embodiment 7, and Embodiment 4 is compared with Embodiment 8. The tensile strength of the anion exchange membrane of Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 is smaller, the elongation at break is larger, the water absorption rate is smaller, the swelling rate is larger, the conductivity is smaller, the ion exchange capacity (IEC) is smaller, and the polarization performance is larger. The reason is that the monomer type and the consumption containing phenyl used in Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 are different, so that the grafting rate of the quaternizing agent in the anion exchange polymer is higher. It can be seen that by controlling the monomer type and the consumption containing phenyl, the grafting rate of the quaternizing agent in the anion exchange polymer can be controlled.

[0195] Embodiment 2 is compared with comparative example 1, and embodiment 6 is compared with comparative example 2, and the ion exchange capacity (IEC) of the two is close, and it can be seen that the grafting rate of quaternary ammonium reagent in the anion exchange polymer of the two is close, and the nitrogen-containing heterocyclic ketone compound type and consumption of the two are identical, but the monomer, quaternary ammonium reagent and strong acid catalyst containing phenyl consumed are more. It can be seen that the application can improve the grafting rate by carrying out polymerization reaction with the monomer containing phenyl with quaternary ammonium salt ionic liquid, and the consumption of strong acid catalyst can be reduced, and embodiment 2 does not use the solvent used by comparative example (methylene chloride, which has toxicity), and the post-processing cost can be reduced.

[0196] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. An anion exchange polymer, characterized in that comprising structural units represented by formula (1) and / or formula (2), Wherein, A in formula (1) and formula (2) independently comprises One or more of, wherein R1, R2 and R are independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring; A r1 and A r2 It is a phenyl-containing monomer.

2. The anion exchange polymer according to claim 1, characterized in that: The A r1 include One or more of; and / or The A r2 include One or more of; and / or The anion exchange polymer further comprises one or more of trifluoroacetate ion, p-toluenesulfonate ion, iodide ion, bromide ion, methanesulfonate ion, ethanesulfonate ion, but-3-yn-1-ylmethanesulfonate ion, allylsulfonate ion, benzenesulfonate ion, nitrobenzenesulfonate ion, trifluoromethanesulfonate ion, trifluoromethanesulfonate ion, toluenesulfonate ion, toluene-4-sulfonate ion, toluenesulfonate ion, neopentylbenzenesulfonate ion, tetrahydro-2H-pyran-4-ylmethanesulfonate ion and p-toluenesulfonate ion; and / or The structural formula of the anion exchange polymer is Among them, the ratio of X to Y is (85-95):(5-15).

3. A method for preparing an anion exchange polymer, characterized in that: include: Providing a nitrogen-containing heterocyclic ketone compound and a quaternizing agent, and subjecting the nitrogen-containing heterocyclic ketone compound and the quaternizing agent to a quaternization reaction to obtain a quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound; Providing a phenyl-containing monomer and a strong acid catalyst, mixing the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound with the phenyl-containing monomer and the strong acid catalyst, so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the phenyl-containing monomer undergo a polymerization reaction to obtain an initial reaction product; The initial reaction product is subjected to precipitation treatment to obtain an anion exchange polymer.

4. The method for preparing an anion exchange polymer according to claim 3, characterized in that: The nitrogen-containing heterocyclic ketone compounds include One or more of, wherein R1, R2 and R are independently one of hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, hydroxyl and aromatic ring; and / or The quaternizing agent comprises one or more of methyl trifluoroacetate, methyl p-toluenesulfonate, iodomethane, propyl bromide, ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, ethyl bromide, butyl bromide, pentyl bromide, hexyl bromide, cyclohexyl bromide, cyclopentyl bromide, cyclohexyl bromide, methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate, ethyl ethanesulfonate, but-3-yn-1-yl methanesulfonate, allyl allyl sulfonate, methyl benzenesulfonate, methyl nitrobenzenesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, ethyl toluenesulfonate, toluene-4-sulfonic acid cyclobutyl ester, butyl toluenesulfonate, neopentylbenzenesulfonate, tetrahydro-2H-pyran-4-yl methanesulfonate and cyclohexyl p-toluenesulfonate; and / or The phenyl-containing monomers include One or more of; The strong acid catalyst includes one or more of trifluoromethanesulfonic acid, pentafluoropropionic acid, trifluoroacetic acid, trifluoromethanesulfonic acid and heptafluorobutyric acid.

5. The method for preparing an anion exchange polymer according to claim 3, characterized in that: The molar ratio of the nitrogen-containing heterocyclic ketone compound to the quaternizing agent is 10:(8-12); and / or The molar ratio of the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound, the phenyl-containing monomer and the strong acid catalyst is (1-2):1:(4-8); and / or The weight average molecular weight of the anion exchange polymer is 40000 g / mol-500000 g / mol.

6. The method for preparing an anion exchange polymer according to claim 3, characterized in that: The step of carrying out a quaternization reaction between the nitrogen-containing heterocyclic ketone compound and the quaternizing agent comprises: providing a first solvent, mixing the nitrogen-containing heterocyclic ketone compound in the first solvent, and then adding the quaternizing agent to carry out a quaternization reaction; and / or The temperature of the quaternization reaction is 10°C-100°C, and the time of the quaternization reaction is 1h-36h; and / or The step of mixing the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound with the monomer containing phenyl and the strong acid catalyst so that the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound and the monomer containing phenyl undergo a polymerization reaction comprises: mixing the quaternary ammonium salt ionic liquid of the nitrogen-containing heterocyclic ketone compound with the monomer containing phenyl, and then adding the strong acid catalyst to undergo a polymerization reaction; and / or The temperature when the strong acid catalyst is added is -5°C to 0°C; and / or The polymerization reaction temperature is 0°C-24°C, and the polymerization reaction time is 1h-15h.

7. The method for preparing an anion exchange polymer according to claim 3, characterized in that: After the quaternization reaction, the method further includes: first washing, filtering and first drying the product of the quaternization reaction.

8. The method for preparing anion exchange polymer according to claim 3, characterized in that: The reagent used for the first washing includes one or more of ethanol, ethyl acetate, ethylene glycol, ether, tetrahydrofuran, acetone and water; and / or The first drying temperature is 60° C.-100° C., and the first drying time is 8 h-12 h.

9. The method for preparing an anion exchange polymer according to claim 3, characterized in that: The precipitation treatment comprises: placing the initial reaction product in water and precipitating a crude anion exchange polymer; After the precipitation treatment, the method further comprises: performing a second washing on the product obtained by the precipitation treatment, and then performing a second drying.

10. The method for preparing anion exchange polymer according to claim 9, characterized in that: The detergent used in the second washing comprises one or more of water and an inorganic salt solution; and / or The temperature of the second drying is 60° C.-100° C., and the time of the second drying is 22 h-26 h.

11. A method for preparing an anion exchange membrane, characterized in that: The following steps are involved: A second solvent and the anion exchange polymer according to any one of claims 1 to 8 are provided, the anion exchange polymer is dissolved in the second solvent, and then subjected to membrane forming treatment to obtain an anion exchange membrane.

12. The method for preparing an anion exchange membrane according to claim 11, characterized in that: The second solvent comprises one or more of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and acetonitrile; and / or The solid content of the solution obtained by dissolving the anion exchange polymer in the second solvent is 17 wt % to 20 wt %.

13. The method for preparing an anion exchange membrane according to claim 11, characterized in that: The film forming process comprises: forming a wet film and then performing a first drying; and / or Before the film forming treatment, the method further comprises: filtering the solution obtained by dissolving the anion exchange polymer in the second solvent, wherein the pore size of the filter used for the filtration is 2000 mesh to 6000 mesh.

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