A photopolymerizable anion exchange membrane and a method for preparing the same

Abstract

The application discloses a kind of photopolymerization anion exchange membrane and preparation method thereof, belong to ion exchange membrane technical field.Clopropylmethyl styrene, tripropylene glycol dipropyl acrylate and photo initiator are mixed and stirred to obtain casting solution, then the casting solution is coated on glass plate, and the base film is prepared by using ultraviolet irradiation to initiate photopolymerization, then the base film is modified to obtain the required anion exchange membrane.The anion exchange membrane provided by the application can completely avoid the use of organic solvent during preparation, and has significant environmental and economic benefits.Meanwhile, the photopolymerization technology used has the advantages of simple operation, low energy consumption, fast polymerization rate, etc.The prepared anion exchange membrane has excellent desalination performance, and has a large-scale application prospect in the field of electrodialysis seawater desalination.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion exchange membranes, and particularly relates to a photopolymerization anion exchange membrane and a preparation method thereof. BACKGROUND

[0002] Electrodialysis is an effective seawater desalination technology, and the performance of an anion exchange membrane as a core component of an electrodialyzer directly affects the effect of electrodialysis. Compared with a cation exchange membrane, the preparation process and performance of an anion exchange membrane are still insufficient to meet the needs of large-scale application. It must be noted that the preparation of the existing anion exchange membrane generally needs to use an organic solvent as a reaction medium, and the use and treatment of the organic solvent not only increase the membrane preparation cost, but also cause serious environmental pollution.

[0003] CN202310353719.2 discloses a preparation method of an anion exchange membrane. First, brominated polyphenyl ether and polyethylene imine are dissolved in dimethylformamide (DMF), dimethylacetamide (DMAc) or N-methyl pyrrolidone (NMP) to form a uniform solution, then N-butyl imidazole is added to the brominated polyphenyl ether solution to react at 25-60 ℃ for 8-24 hours to obtain imidazole functionalized brominated polyphenyl ether, then polyethylene imine is added and stirred to obtain an imidazole functionalized PEI blended brominated polyphenyl ether solution. Finally, it is cast on a clean glass plate and dried at 80 ℃ for 12-36 hours to obtain a homogeneous brominated polyphenyl ether anion exchange membrane. CN202310757811.5 discloses a preparation method of an anion exchange membrane. First, polyvinylidene fluoride is dissolved in N,N-dimethylformamide (DMF) to obtain a transparent solution, then vinylbenzyltrimethylammonium chloride, dimethylaminoethyl methacrylate and divinylbenzene, and benzoyl peroxide are sequentially added to the transparent solution for dissolution and stirring, and reacted at 80-90 ℃ for 8-12 hours. Then, 1,4-p-dichlorobenzene dissolved in DMF is added, and reacted at 70-90 ℃ for 6-8 hours to obtain a brown transparent solution. The solution is coated on a glass plate and vacuum dried at 60-90 ℃ for 12-24 hours to remove DMF, and finally an anion exchange membrane is obtained. The above method has problems such as complicated preparation process, long time, and use of toxic organic solvents, and therefore it is necessary to find a simple, efficient and green anion exchange membrane preparation method. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a photopolymerization anion exchange membrane for electrodialysis and a preparation method thereof to overcome the above-mentioned problems and provide a simpler, more environmentally friendly and efficient way for the preparation of an anion exchange membrane for electrodialysis.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The application discloses a method for preparing an anion exchange membrane through photopolymerization, and specifically comprises the following steps: mixing and stirring p-chloromethylstyrene (VBC), tripropylene glycol diacrylate (TPGDA) and a photoinitiator to obtain a casting solution, coating the casting solution on a glass plate, irradiating the casting solution with ultraviolet light to initiate photopolymerization and prepare a base film, and finally immersing the base film in a modifier solution to perform positive charge modification and obtain the anion exchange membrane prepared through photopolymerization.

[0007] The photoinitiator is 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone or 2-methyl-1-[4-methylthiophenyl]-2-morpholinyl-1-propanone.

[0008] The mass ratio of the p-chloromethylstyrene, the tripropylene glycol diacrylate and the photoinitiator is 1:(0.03-0.10):(0.03-0.08).

[0009] The light irradiation curing time is 5 minutes or longer.

[0010] The modifier is one of N-substituted imidazoles and tertiary amines, and the solvent is one of water, methanol, ethanol and acetone.

[0011] The concentration of the modifier solution is 0.1-3 mol / L, and the temperature is 25-100 DEG C.

[0012] The immersion time of the base film in the modifier solution is 0.1 h-48 h.

[0013] Compared with the prior art, the application has the beneficial effects that:

[0014] (1) The method can completely avoid the increase of membrane preparation cost and environmental pollution caused by the use of organic solvents, and has remarkable economic and environmental benefits.

[0015] (2) The process is simple, the time is short, and the material cost is low, so that the membrane preparation cost can be effectively reduced.

[0016] (3) Compared with the commercial AMV membrane, the anion exchange membrane prepared by the application has more excellent desalination performance in the laboratory electro-dialysis desalination test, and is beneficial to large-scale production and application due to the low cost and simple process. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is an FT-IR spectrum of a base film prepared through photopolymerization of VBC and TPGDA in Example 1 and an anion exchange membrane obtained after the base film is modified by 1-methylimidazole.

[0018] Figure 2The cross-section SEM images of the base membrane obtained by photopolymerization of VBC and TPGDA in Example 1 and the anion exchange membrane obtained by modifying the base membrane with 1-methylimidazole. DETAILED DESCRIPTION

[0019] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.

[0020] The chemical reagents used in the embodiments of the present application are all commercially available.

[0021] Example 1

[0022] 1 g of VBC monomer was mixed with 0.10 g of TPGDA crosslinking agent and 0.033 g of 2-hydroxy-2-hydroxy-1-phenyl-1-propanone initiator to obtain a casting solution. The casting solution was cast on a glass plate, and a base membrane was obtained by irradiating with a 365 nm ultraviolet light for 5 min to initiate free radical polymerization. Then, the base membrane was soaked in a 2 mol / L 1-methylimidazole aqueous solution at 60 ℃ for 2.5 h for positive charge modification to obtain a photopolymerization anion exchange membrane.

[0023] The photopolymerization anion exchange membrane prepared above was subjected to electrodialysis desalination performance test, and the desalination performance was compared with that of the Japanese product membrane AMV. The experimental conditions were as follows: the effective membrane area was 7.065 cm 2 , the desalination system was 0.1 mol / L NaCl solution, the operating current was 0.11 A, and the desalination time was 270 min. The tensile strength obtained in this embodiment was 21.78 MPa, and the electrodialysis desalination performance test results showed that the NaCl removal rate was 92.09%, the current efficiency was 95.35%, and the membrane stack energy consumption was 5.97 kWh·kg -1 . The NaCl removal rate of the product membrane AMV was 79.44%, the current efficiency was 87.45%, and the membrane stack energy consumption was 6.84 kWh·kg -1 .

[0024] Compared with the product membrane AMV, the electrodialysis desalination performance of the anion exchange membrane prepared in this embodiment was more excellent, specifically, the NaCl removal rate was increased by 15.92%, the current efficiency was increased by 9.03%, and the membrane stack energy consumption was reduced by 12.72%. The above results showed that the positive charge modification with 1-methylimidazole formed a large number of charged groups in the membrane, thereby meeting the demand of practical application of electrodialysis desalination.

[0025] Example 2

[0026] A casting solution was prepared by mixing 1 g of VBC monomer, 0.03 g of TPGDA crosslinking agent and 0.0618 g of 2-hydroxy-2-hydroxy-1-phenyl-1-propanone initiator. The casting solution was cast on a glass plate and subjected to radical polymerization by irradiation with ultraviolet light at a wavelength of 365 nm for 35 min to obtain a base film. The base film was then soaked in a 2 mol / L aqueous 1-methylimidazole solution at 60°C for 2.5 h to perform positive charge modification, thereby obtaining a photopolymerized anion exchange membrane.

[0027] The electrodialysis desalination test was performed under the same conditions as in Example 1. The tensile strength obtained in this example was 21.32 MPa, and the results of the electrodialysis desalination performance test were as follows: the NaCl removal rate was 90.55%, the current efficiency was 93.73%, and the membrane stack energy consumption was 6.17 kWh·kg -1 . Compared with the commercial membrane AMV, the NaCl removal rate was increased by 13.98%, the current efficiency was increased by 7.18%, and the membrane stack energy consumption was reduced by 16.20%.

[0028] Example 3

[0029] An anion exchange membrane was prepared by the same method as in Example 1, except that the content of the photoinitiator was changed to 3% relative to the content of VBC, the photopolymerization time was changed to 25 min, and the other conditions were unchanged, thereby obtaining a photopolymerized anion exchange membrane.

[0030] The electrodialysis desalination test was performed under the same conditions as in Example 1. The tensile strength obtained in this example was 21.16 MPa, and the results of the electrodialysis desalination performance test were as follows: the NaCl removal rate was 90.32%, the current efficiency was 93.65%, and the membrane stack energy consumption was 6.02 kWh·kg -1 .

[0031] Example 4

[0032] An anion exchange membrane was prepared by the same method as in Example 1, except that the content of the photoinitiator was changed to 8% relative to the content of VBC, the photopolymerization time was changed to 60 min, and the other conditions were unchanged, thereby obtaining a photopolymerized anion exchange membrane.

[0033] The electrodialysis desalination test was performed under the same conditions as in Example 1. The tensile strength obtained in this example was 20.83 MPa, and the results of the electrodialysis desalination performance test were as follows: the NaCl removal rate was 89.41%, the current efficiency was 91.66%, and the membrane stack energy consumption was 6.07 kWh·kg -1 .

[0034] Example 5

[0035] The photopolymerization anion exchange membrane was prepared by the similar method of Example 1, except that the photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone was changed to 2-hydroxy-1-(4-(2-hydroxy-2-methylpropanoyl)benzyl)-2-methyl-1-propanone, the photopolymerization time was changed to 10 min, and the other conditions were unchanged, to obtain the photopolymerization anion exchange membrane.

[0036] The electrodialysis desalination test was carried out under the same conditions of Example 1. The tensile strength obtained in this example was 22.55 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 93.47%, current efficiency was 95.82%, and membrane stack energy consumption was 5.81 kWh·kg -1 .

[0037] Example 6

[0038] The photopolymerization anion exchange membrane was prepared by the similar method of Example 1, except that the 1-methylimidazole aqueous solution was changed to a trimethylamine methanol solution, and the other conditions were unchanged, to obtain the photopolymerization anion exchange membrane.

[0039] The electrodialysis desalination test was carried out under the same conditions of Example 1. The tensile strength obtained in this example was 22.81 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 93.68%, current efficiency was 94.79%, and membrane stack energy consumption was 5.87 kWh·kg -1 .

[0040] Example 7

[0041] The photopolymerization anion exchange membrane was prepared by the similar method of Example 1, except that the 1-methylimidazole aqueous solution was changed to a 1,2-dimethylimidazole acetone solution, and the other conditions were unchanged, to obtain the photopolymerization anion exchange membrane.

[0042] The electrodialysis desalination test was carried out under the same conditions of Example 1. The tensile strength obtained in this example was 22.58 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 93.22%, current efficiency was 95.06%, and membrane stack energy consumption was 5.58 kWh·kg -1 .

[0043] Example 8

[0044] The photopolymerization anion exchange membrane was prepared by the similar method of Example 1, except that the 1-methylimidazole aqueous solution was changed to a triethylamine ethanol solution, and the other conditions were unchanged, to obtain the photopolymerization anion exchange membrane.

[0045] The same conditions as in Example 1 were used for the electrodialysis desalination test. The tensile strength obtained in this example was 22.07 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 92.96%, current efficiency was 94.85%, and membrane stack energy consumption was 5.63 kWh·kg -1 .

[0046] Example 9

[0047] A similar method as in Example 1 was used to prepare the photopolymerization anion exchange membrane, except that the immersion temperature of the base film in the 1-methylimidazole aqueous solution was 25 ℃, the immersion time was changed to 48 h, and other conditions remained unchanged, to obtain the photopolymerization anion exchange membrane.

[0048] The same conditions as in Example 1 were used for the electrodialysis desalination test. The tensile strength obtained in this example was 21.32 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 90.23%, current efficiency was 92.62%, and membrane stack energy consumption was 5.83 kWh·kg -1 .

[0049] Example 10

[0050] A similar method as in Example 1 was used to prepare the photopolymerization anion exchange membrane, except that the concentration of the 1-methylimidazole aqueous solution was changed to 0.1 mol / L, the immersion time was changed to 36 h, and other conditions remained unchanged, to obtain the photopolymerization anion exchange membrane.

[0051] The same conditions as in Example 1 were used for the electrodialysis desalination test. The tensile strength obtained in this example was 20.37 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 88.17%, current efficiency was 89.06%, and membrane stack energy consumption was 5.97 kWh·kg -1 .

[0052] Example 11

[0053] A similar method as in Example 1 was used to prepare the photopolymerization anion exchange membrane, except that the immersion temperature of the base film in the 1-methylimidazole aqueous solution was 100 ℃, the immersion time was changed to 0.1 h, and other conditions remained unchanged, to obtain the photopolymerization anion exchange membrane.

[0054] The same conditions as in Example 1 were used for the electrodialysis desalination test. The tensile strength obtained in this example was 19.85 MPa, and the electrodialysis desalination performance test results were: NaCl removal rate was 86.36%, current efficiency was 87.25%, and membrane stack energy consumption was 6.13 kWh·kg -1 .

[0055] Example 12

[0056] The photo-polymerization preparation of an anion exchange membrane was prepared by using the similar method of Example 1, only the concentration of the 1-methyl imidazole aqueous solution was changed to 3 mol / L, the soaking time was changed to 1 h, and other conditions were not changed, to obtain the photo-polymerization anion exchange membrane.

[0057] The electrodialysis desalination test was carried out under the same conditions of Example 1. The tensile strength obtained in this example was 20.03 MPa, and the electrodialysis desalination performance test results were as follows: the NaCl removal rate was 87.41%, the current efficiency was 87.86%, and the membrane stack energy consumption was 6.05 kWh·kg -1 .

[0058] The above only describes the preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.

Claims

1. Use of a photopolymerized anion exchange membrane in electrodialytic seawater desalination, characterized in that: The preparation method of the photo-polymerization anion exchange membrane comprises the following steps: uniformly mixing p-chloromethyl styrene, tripropyleneglycol diacrylate and a photo initiator to obtain a casting solution; coating the casting solution on a glass plate and irradiating the casting solution with ultraviolet light to initiate photo polymerization, thereby obtaining a base film; and immersing the base film in a modifier solution to perform positive charge modification, thereby obtaining the photo-polymerization anion exchange membrane. The solute in the modifier solution is N-substituted imidazole or a tertiary amine, and the solvent is one of water, methanol, ethanol and acetone. The concentration of the modifier solution is 0.1-3 mol / L, and the temperature is 25-100 DEG C; the immersion time is 0.1 h-48 h.

2. Use according to claim 1, characterized in that: The photo initiator is one of 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone and 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone.

3. Use according to claim 1, characterized in that: The mass ratio of p-chloromethyl styrene, tripropyleneglycol diacrylate and the photo initiator is 1:0.03-0.10:0.03-0.

08.

4. Use according to claim 1, characterized in that: The irradiation time is not less than 5 minutes.

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