CN117717913A - Ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane and preparation method and application thereof - Google Patents
Ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane and preparation method and application thereof Download PDFInfo
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- CN117717913A CN117717913A CN202311660992.6A CN202311660992A CN117717913A CN 117717913 A CN117717913 A CN 117717913A CN 202311660992 A CN202311660992 A CN 202311660992A CN 117717913 A CN117717913 A CN 117717913A
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- -1 polyethylene Polymers 0.000 title claims abstract description 149
- 239000004698 Polyethylene Substances 0.000 title claims abstract description 128
- 239000003011 anion exchange membrane Substances 0.000 title claims abstract description 119
- 229920000573 polyethylene Polymers 0.000 title claims abstract description 113
- 239000002131 composite material Substances 0.000 title claims abstract description 93
- 238000002360 preparation method Methods 0.000 title claims abstract description 31
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 222
- 229920000554 ionomer Polymers 0.000 claims abstract description 85
- 238000000909 electrodialysis Methods 0.000 claims abstract description 65
- 238000010612 desalination reaction Methods 0.000 claims abstract description 57
- 150000002500 ions Chemical class 0.000 claims abstract description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 230000035699 permeability Effects 0.000 claims abstract description 36
- 238000005265 energy consumption Methods 0.000 claims abstract description 31
- 239000012528 membrane Substances 0.000 claims abstract description 31
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 230000004907 flux Effects 0.000 claims abstract description 23
- 239000012153 distilled water Substances 0.000 claims abstract description 11
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 238000005349 anion exchange Methods 0.000 claims abstract description 9
- 238000002791 soaking Methods 0.000 claims abstract description 7
- 239000011248 coating agent Substances 0.000 claims abstract description 4
- 238000000576 coating method Methods 0.000 claims abstract description 4
- 238000002156 mixing Methods 0.000 claims abstract description 4
- 239000000243 solution Substances 0.000 claims description 73
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 72
- 239000011780 sodium chloride Substances 0.000 claims description 36
- 238000010521 absorption reaction Methods 0.000 claims description 22
- 230000008961 swelling Effects 0.000 claims description 22
- 238000003756 stirring Methods 0.000 claims description 21
- 239000011521 glass Substances 0.000 claims description 17
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 14
- VIOJQBMMOKZZMO-UHFFFAOYSA-N 2-(2,6-dimethylphenoxy)-1,3-dimethylbenzene Chemical class CC1=CC=CC(C)=C1OC1=C(C)C=CC=C1C VIOJQBMMOKZZMO-UHFFFAOYSA-N 0.000 claims description 13
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 11
- NAPSCFZYZVSQHF-UHFFFAOYSA-N dimantine Chemical compound CCCCCCCCCCCCCCCCCCN(C)C NAPSCFZYZVSQHF-UHFFFAOYSA-N 0.000 claims description 10
- 239000012267 brine Substances 0.000 claims description 8
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims description 8
- 238000005507 spraying Methods 0.000 claims description 8
- QMDUPVPMPVZZGK-UHFFFAOYSA-N n,n-dimethyloctadecan-1-amine;hydrobromide Chemical compound [Br-].CCCCCCCCCCCCCCCCCC[NH+](C)C QMDUPVPMPVZZGK-UHFFFAOYSA-N 0.000 claims description 7
- JAZLRZHALORNSI-UHFFFAOYSA-N 4-octadecyl-1-aza-4-azoniabicyclo[2.2.2]octane Chemical compound C1CN2CC[N+]1(CCCCCCCCCCCCCCCCCC)CC2 JAZLRZHALORNSI-UHFFFAOYSA-N 0.000 claims description 4
- 125000005997 bromomethyl group Chemical group 0.000 claims description 4
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 abstract description 20
- 230000002209 hydrophobic effect Effects 0.000 description 42
- 230000000052 comparative effect Effects 0.000 description 29
- 125000004079 stearyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 27
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 24
- 238000001000 micrograph Methods 0.000 description 20
- VKRWRNVGVPSVLA-UHFFFAOYSA-N n,n'-bis(2-phenylphenyl)oxamide Chemical compound C=1C=CC=C(C=2C=CC=CC=2)C=1NC(=O)C(=O)NC1=CC=CC=C1C1=CC=CC=C1 VKRWRNVGVPSVLA-UHFFFAOYSA-N 0.000 description 17
- 238000012360 testing method Methods 0.000 description 11
- 239000002904 solvent Substances 0.000 description 10
- 239000010410 layer Substances 0.000 description 9
- 239000011159 matrix material Substances 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 8
- 238000011049 filling Methods 0.000 description 8
- 239000003014 ion exchange membrane Substances 0.000 description 7
- 239000011259 mixed solution Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000002344 surface layer Substances 0.000 description 5
- 238000009210 therapy by ultrasound Methods 0.000 description 5
- 230000037303 wrinkles Effects 0.000 description 5
- 125000002091 cationic group Chemical group 0.000 description 4
- 239000005357 flat glass Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 230000007480 spreading Effects 0.000 description 4
- 238000003892 spreading Methods 0.000 description 4
- 150000001450 anions Chemical class 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000005341 cation exchange Methods 0.000 description 3
- 238000012512 characterization method Methods 0.000 description 3
- 230000032798 delamination Effects 0.000 description 3
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- 238000005259 measurement Methods 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 230000002787 reinforcement Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical class [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010382 chemical cross-linking Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
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- 238000011033 desalting Methods 0.000 description 2
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- 239000012895 dilution Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000004676 glycans Chemical class 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229920002521 macromolecule Polymers 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000002114 nanocomposite Substances 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920013636 polyphenyl ether polymer Polymers 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- RAXXELZNTBOGNW-UHFFFAOYSA-O Imidazolium Chemical group C1=C[NH+]=CN1 RAXXELZNTBOGNW-UHFFFAOYSA-O 0.000 description 1
- 229920000557 Nafion® Polymers 0.000 description 1
- 239000004693 Polybenzimidazole Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000031709 bromination Effects 0.000 description 1
- 238000005893 bromination reaction Methods 0.000 description 1
- 239000003010 cation ion exchange membrane Substances 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
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- 150000008040 ionic compounds Chemical class 0.000 description 1
- 239000002608 ionic liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 125000005496 phosphonium group Chemical group 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920001643 poly(ether ketone) Polymers 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920002480 polybenzimidazole Polymers 0.000 description 1
- 229920001955 polyphenylene ether Polymers 0.000 description 1
- 229920006380 polyphenylene oxide Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- JUJWROOIHBZHMG-UHFFFAOYSA-O pyridinium Chemical group C1=CC=[NH+]C=C1 JUJWROOIHBZHMG-UHFFFAOYSA-O 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses an ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane, and a preparation method and application thereof. The ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane is prepared by uniformly mixing an ionomer solution with ethanol, coating the mixture on the ultrathin microporous polyethylene membrane, removing volatile matters to obtain a dry film, and fully soaking the dry film in distilled water. According to the invention, the ultra-thin microporous polyethylene film of the substrate is treated by ethanol, so that the surface property of the substrate is changed, ethanol is added into the ionomer solution, the property of the ionomer solution is changed, and then the ionomer is deposited and aggregated on the substrate in the film preparation process, so that the ultra-thin composite anion exchange film with high ion selective permeability, low surface resistance and high mechanical property is obtained. The invention effectively solves the problem that the existing anion exchange membrane cannot achieve high ion permeation selectivity, low surface resistance and high mechanical property, and the developed ultrathin high-performance anion exchange membrane has the characteristics of high current efficiency, salt flux and low energy consumption of desalination and electrodialysis.
Description
Technical Field
The invention relates to an anion exchange membrane, in particular to an ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane, a preparation method and application thereof, wherein the ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane is used for electrodialysis desalination of brine; belonging to the technical field of electrodialysis desalination.
Background
In Electrodialysis (ED) it is necessary for Ion Exchange Membranes (IEMs) to selectively move components of different nature in a mixed solution of ionic compounds from one compartment (diluting compartment) to another (concentrating compartment) under the action of an electric drive. This requires that IEM must have satisfactory mechanical, chemical and dimensional stability to meet long-term use, and also high ion permeation selectivity (P) and low sheet resistance (R m ) To ensure high electrodialysis current efficiency (eta) and low Energy Consumption (EC). The existing Nafion and other Cation Exchange Membranes (CEM) basically can meet the requirements, but the performance of the Anion Exchange Membranes (AEMs) used for electrodialysis needs to be further improved. Because of the limitations of cation exchange membrane applications, the development of AEMs with high ion permselectivity, conductivity, and mechanical properties is critical to the development of upgrades in ED technology.
In order to find ideal AEMs that meet ED with high dialysis current efficiency, low energy consumption and high mechanical properties at the same time, researchers have developed a variety of polymer backbones, mainly polysulfone, polyetherketone, polyphenylene oxide, aliphatic polymers, etc., and cationic structural groups, which are quaternary ammonium, quaternary phosphonium, pyridinium, imidazolium, etc. Recently, wei et al (B.Wei, J.Pan, J.Feng, C.Chen, S.Liao, Y.Yu, X.Li, highly conductive and permselective anion exchange membranes for electrodialysis Desalination with series-connected dications appending flexible hydrophobic tails, desalination,474 (2020) 114184.) developed an anion exchange membrane QPT-4 (p=94%, R) of hydrophobic hexyl-modified tandem biscationic ionomers with good ED performance m ＝1.60Ωcm 2 ) The current efficiency (. Eta.) was 89.14%, the salt flux (J) was 75.57mg m -2 s -1 Energy Consumption (EC) of 2.16kWh kg -1 NaCl, mechanical properties: the tensile strength was 10.4MPa, and the elongation at break was 7.10%. The tensile strength of the simple ionomer AEMs is lower, and the requirements of long-time ED operation can be met only by increasing the mechanical property of the thickness, and the thickness of the simple ionomer AEMs is generally 100-200 microns.
In order to further improve the physical and electrochemical properties of the AEMs, researchers have used chemical cross-linking (G.Peng, C.Zhu, J.Liao, X.Gao, L.Hao, A.Sotto, J.Shen, a two-step strategy for the preparation of anion-exchange membranes based on Poly) for electrodialysis desalination, polymer,218 (2021) 123508), inorganic nanoparticle doping (J.G.Hong, Y.Chen, nanocomposite Reverse Electrodialysis (RED) ion-exchange membranes for salinity gradient power generation, journal of Membrane Science,460 (2014) 139-147), organic Polymer blending (Y.Li, A.C.Jackson, F.L.Beyer, D.M.Knauss, poly (2, 6-dimethyl-1,4-phenyl oxide) Blended with Poly (vinylbenzyl chloride) -b-polystyrene for the Formation of Anion Exchange Membranes, macromolecules,47 (2014) 6757), ionomer microporous membrane filling (B.Wang, J.Yan, H.Wang, R.Li, R.Fu, C.Jiang, V.Nikonenko, N.Pismenskaya, Y.Wang, T.Xu, ionic liquid-filled with ion-exchange membranes enable fast large-sized metallic anion migration in electrodialysis, journal of Membrane Science, 2023) 121348) and the like to design and prepare a plurality of AEMs, recently, hydrogen bonding (7432) of the 4-phenyl oxide) Blended with Poly (vinylbenzyl chloride) -b-polystyrene for the Formation of Anion Exchange Membranes, macromolecules,47 (2014) 6757), and the like, and recently, hydrogen bonding (7432) of the 4-modified polysaccharide (7432) has been developed The surface resistance (R) of the sub-exchange membrane HQPsf-CS-3% m ) And P is 2.41 Ω cm respectively 2 And 96.86%, tensile strength of 11.0MPa, HQPsf-CS-3% also exhibits good ED performance with J of 77.8mg cm -2 s -1 EC and η are 4.23kWh kg, respectively -1 NaCl and 93.30%. Studies of Szekelys report that polybenzimidazole-based AEMs doped with organically modified graphene oxide improve ion-selective permeability. M2-1 has the highest ion selective permeability, P reaches 98%, tensile strength is 43MPa, eta is 100%, and EC is 10.1kWh kg -1 NaCl (L.Cseri, J.Baugh, A.Alabi, A.AlHajaj, L.Zou, R.A.W.Dryfe, P.M.Budd, G.Szekely, graphene oxide-polybenzimidazolium nanocomposite anion exchange membranes for electrodialysis, journal of Materials Chemistry A,6 (2018) 24728-24739). Recently, bruggen et al (F.Deboli, B.Van der Bruggen, M.L.Donten, A versatile chemistry platform for the fabrication of cost-effective hierarchical cation and anion exchange membranes, desamination, 535 (2022) 115794) passed through porous PVC-SiO 2 The substrate adsorbs acrylic acid ionomer and uses ultraviolet crosslinking to prepare an ion exchange membrane, the optimal P-permselectivity of developed hAEM ions can reach 94%, the film thickness is 420 mu m, and the corresponding surface resistance R m Is 6.44 Ω cm 2 The ED current efficiency eta reaches 93.3 percent, and the final desalination rate is 56 percent.
The prior art chemical crosslinking method enhances the mechanical properties of the membrane, but increases the control difficulty of the membrane preparation process, and has limited improvement on the ion selective permeability of the AEMs because the intrinsic ionomer structure of the AEMs is not changed; other materials with limited compatibility or macroscopic phase separation between the ionomer and the reinforcement material of the composite reinforcement technology do not achieve the purpose of synchronously enhancing the mechanical property, ion conductivity and ion selective permeability of AEMs, and the thickness of the composite membrane material is generally thicker, the surface resistance is larger and the energy consumption is higher.
Disclosure of Invention
In order to solve the defects of the prior art, the invention aims to provide an ultrathin high-performance composite anion exchange membrane with high ion permeation selectivity, low surface resistance and high mechanical performance and a preparation method thereof.
Another object of the present invention is to provide the use of ultra-thin high performance composite anion exchange membranes in electrodialysis desalination.
In order to achieve the above object, the present invention provides the following technical solutions.
The ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane is characterized in that an ionomer solution and ethanol are uniformly mixed and then coated on the ultra-thin microporous polyethylene membrane, a dry film is obtained after volatile matters are removed, and the dry film is fully soaked in distilled water to obtain the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane; the ionomer is QPPO-TMEDA-C18, QPPO-DABCO-C18 or QPPO-C18; the structural formula is as follows:
The ionomer corresponding to the above structural formula is specifically as follows:
in order to further achieve the aim of the invention, preferably, the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane has the thickness of 20-50 mu m, the water absorption of 5.44-10.90%, the swelling rate of 1.38-1.61%, the ion selective permeability of 93.68-97.32% and the surface resistance of 1.33 omega cm 2 ～2.23Ωcm 2 The tensile strength is 46.33 MPa-62.19 MPa, and the elongation at break is 119.05-141.33%.
The preparation method of the ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane comprises the following steps:
1) Pretreatment of a substrate: placing the ultrathin microporous polyethylene film on a glass plate after cleaning, completely attaching the ultrathin microporous polyethylene film with the glass plate, spraying ethanol on the surface of the ultrathin microporous polyethylene film until the film is naturally flattened, and naturally volatilizing at room temperature until the surface is dry;
2) Ionomer solution preparation: dissolving brominated poly 2, 6-dimethyl ether in N-methylpyrrolidone, adding N- (2- (dimethylaminoethyl) -N, N, N-dimethyl octadecyl ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-ium or N, N-dimethyl octadecyl amine, and reacting at normal temperature for 48-72 h under stirring to obtain QPPO-TMEDA-C18, QPPO-DABCO-C18 or QPPO-C18 ionomer solution respectively;
3) Preparing a composite film: mixing the ionomer solution obtained in the step 2) with ethanol, coating the mixture on the treated ultrathin microporous polyethylene film, removing volatile components from the composite film at 40-60 ℃ to obtain a dry film, and fully soaking the dry film in distilled water to obtain the ultrathin high-performance composite anion exchange film.
Preferably, in the step (1), the ultra-thin microporous polyethylene film is completely immersed in ethanol for ultrasonic cleaning for 2-5 times.
Preferably, in the step (2), the bromomethylation degree of the brominated poly (2, 6-dimethyl-phenyl ether) is 0.4-0.6.
Preferably, in step (2), the molar ratio of bromomethyl groups of the brominated poly 2, 6-dimethylbenzeneether to N- (2- (dimethylaminoethyl) -N, N, N-dimethyloctadecyl ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-ium or N, N-dimethyloctadecyl amine is 1:1, the concentration of bromomethyl groups of the brominated poly 2, 6-dimethylbenzeneether to N- (2- (dimethylaminoethyl) -N, N, N-dimethyloctadecyl ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-ium or N, N-dimethyloctadecyl amine in the reaction mixture solution is 20 to 30wt%, and the stirring speed is 100 to 200rpm.
Preferably, in step (3), the amount of ethanol added to the ionomer solution and ethanol mixture is from 5 to 25wt%.
Preferably, in the step (3), the mass of the ionomer solution coated on the ultrathin microporous polyethylene film per square centimeter is 0.027g-0.034g, and the volatile removal is realized by heating at 40-60 ℃ for 48-72 h. The thickness range of the obtained ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane is 20-50 microns.
The ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane is applied to electrodialysis desalination of brine.
Preferably, the current efficiency of the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane in brine electrodialysis desalination is 91.34% -95.29%, and the flux is 83.08mg m -2 s -1 ～86.66mg m -2 s -1 The energy consumption is 1.50kWh kg -1 NaCl～2.20kWh kg -1 NaCl。
Compared with the prior art, the invention has the following advantages and beneficial effects:
1) According to the invention, through pre-customizing octadecyl hydrophobic long chain modified poly-2, 6-dimethyl phenyl ether ionomer QPPO-TMEDA-C18, QPPO-DABCO-C18 and QPPO-C18, on one hand, the local high cationic charge density of the intrinsic structure of the composite AEMs ionomer is ensured, and on the other hand, the micro-phase structure of the ionomer in the hole can be modified by utilizing the strong interaction between the flexible hydrophobic long side chain and the ultra-thin microporous polyethylene hole wall, so that the ion selective permeability of the composite membrane is further improved. On the other hand, the thickness of the film is reduced by means of the reinforcement of the ultrathin polyethylene matrix, so that the film resistance of the composite film is reduced, and the conductivity and the mechanical property of the composite film are synchronously enhanced. Third, the composite membrane reduces ionomer usage and is more cost effective. Therefore, the invention effectively solves the problem that the existing anion exchange membrane can not achieve high ion permeation selectivity, low surface resistance and high mechanical property, and the developed ultrathin high-performance anion exchange membrane meets the requirements of comprehensive properties such as high current efficiency, salt flux, low energy consumption and the like of desalination electrodialysis, and has good application prospect.
2) At room temperature, the ultra-thin high-performance composite anion exchange membrane has the water absorption rate of 5.44-10.90%, the swelling rate of 1.38-1.61%, the ion selective permeability of 93.68-97.32% and the surface resistance of 1.33 Ω cm 2 ～2.23Ωcm 2 Mechanical properties: the tensile strength is 46.33 MPa-62.19 MPa, and the elongation at break is 119.05-141.33%. The requirements of the desalination electrodialysis process on the comprehensive performance of the anion exchange membrane are well met.
3) The thickness range of the ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane obtained by the invention is 20-50 microns, and compared with the prior art, the ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane has obvious thickness advantage.
4) The ultra-thin microporous polyethylene enhanced high-performance composite anion exchange membrane obtained by the invention is obviously superior to an ASTOM commercial membrane AMX in electrodialysis desalination, and is suitable for application in brine electrodialysis desalination.
Drawings
FIG. 1 is a scanning electron microscope image of the front side of a substrate microporous PE.
FIG. 2 is a scanning electron microscope image of the side of the substrate microwell PE.
FIG. 3 is a scanning electron microscope image of the reverse side of the substrate microwell PE.
FIG. 4 is a scanning electron microscope image of the front side of the anion exchange membrane obtained in example 1 with 5% EtOH QPPO-TMEDA-C18@PE.
FIG. 5 is a scanning electron microscope image of the 5% EtOH QPPO-TMEDA-C18@PE side face of the anion exchange membrane obtained in example 1.
FIG. 6 is an enlarged scanning electron microscope image of the 5% EtOH QPPO-TMEDA-C18@PE side face of the anion exchange membrane obtained in example 1.
FIG. 7 is a scanning electron microscope image of the reverse side of the anion exchange membrane obtained in example 1 at 5% EtOH QPPO-TMEDA-C18@PE.
FIG. 8 is a scanning electron microscope image of the front side of the anion exchange membrane obtained in example 2 at 15% EtOH QPPO-TMEDA-C18@PE.
FIG. 9 is a scanning electron microscope image of the side of a 15% EtOH QPPO-TMEDA-C18@PE of the anion exchange membrane obtained in example 2.
FIG. 10 is an enlarged scanning electron microscope image of the side of the anion exchange membrane obtained in example 2 at 15% EtOH QPPO-TMEDA-C18@PE.
FIG. 11 is a scanning electron microscope image of the reverse side of the anion exchange membrane obtained in example 2 at 15% EtOH QPPO-TMEDA-C18@PE.
FIG. 12 is a scanning electron microscope image of the front side of the anion exchange membrane obtained in example 3, 25% EtOH QPPO-TMEDA-C18@PE.
FIG. 13 is a scanning electron microscope image of the side of the anion exchange membrane obtained in example 3 at 25% EtOH QPPO-TMEDA-C18@PE.
FIG. 14 is an enlarged scanning electron microscope image of the side of the anion exchange membrane obtained in example 3 at 25% EtOH QPPO-TMEDA-C18@PE.
FIG. 15 is a scanning electron microscope image of the reverse side of the anion exchange membrane obtained in example 3 at 25% EtOH QPPO-TMEDA-C18@PE.
FIG. 16 is a scanning electron microscope image of the front surface of the anion exchange membrane QPPO-TMEDA-C18 obtained in comparative example 1.
FIG. 17 is a scanning electron microscope image of the side of the anion exchange membrane QPPO-TMEDA-C18 obtained in comparative example 1.
FIG. 18 is an enlarged scanning electron microscope image of the side of the anion exchange membrane QPPO-TMEDA-C18 obtained in comparative example 1.
FIG. 19 is a scanning electron microscope image of the reverse side of the anion exchange membrane QPPO-TMEDA-C18 obtained in comparative example 1.
FIG. 20 is a transmission electron microscope image of the anion exchange membrane QPPO-TMEDA-C18 obtained in comparative example 1.
Detailed Description
The technical scheme of the present invention is further described below by referring to specific examples and drawings, but the implementation of the present invention is not limited by the examples, and any other changes, modifications, substitutions, combinations and simplifications that do not depart from the spirit and principle of the present invention should be equivalent to the substitution pattern, and are included in the protection scope of the present invention.
The preparation method of the ultrathin microporous polyethylene reinforced high-performance composite anion exchange membrane is to adjust the solution performance of the ionomer and the aggregation state of the ionomer in the presence of the microporous polyethylene through the assistance of ethanol to obtain the high-performance composite anion exchange membrane with synchronously reinforced conductivity, selectivity and mechanical properties, and the ultrathin high-performance composite anion exchange membrane is suitable for the electrodialysis desalination process of brine.
The invention constructs an ethanol-assisted micropore filling composite process with an ultrathin micropore polyethylene film as a matrix with high mechanical properties, develops a high-performance composite anion exchange film, greatly improves the mechanical properties of AEMs, reduces the film thickness and the ionomer consumption, and has better cost benefit. The octadecyl hydrophobic long chain modified poly (2, 6-dimethyl phenyl ether) ionomer QPPO-TMEDA-C18, QPPO-DABCO-C18 and QPPO-C18 of the invention maintains the local cationic charge density of the composite AEMs on one hand, and modifies the microphase structure of the ionomer in the hole by utilizing the strong interaction of the flexible hydrophobic long side chain and the microporous polyethylene hole wall on the other hand, thereby further improving the ion selective permeability of the composite film. The combination property is obviously superior to that of intrinsic films QPPO-TMEDA-C18, QPPO-DABCO-C18, QPPO-C18 and commercial film AMX. The problems that the existing anion exchange membrane cannot achieve high ion permeation selection, low surface resistance and high mechanical performance are effectively solved, and the requirements of the desalination electrodialysis process on the comprehensive performance of the anion exchange membrane can be met.
Preferably, the preparation method of the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane is an ethanol-assisted microporous filling composite process, and comprises the following steps:
1) Pretreatment of a substrate: placing an ultrathin microporous polyethylene film into ethanol for ultrasonic cleaning for 3-5 times, then placing the cleaned ultrathin microporous polyethylene film (6 cm multiplied by 15 cm) on a glass plate to enable the ultrathin microporous polyethylene film to be completely attached to the glass plate, continuously spraying ethanol on the surface of the polyethylene film until the film is naturally flattened, and naturally volatilizing at room temperature until the surface is dry;
2) Ionomer solution preparation: brominated poly (2, 6-dimethyl-phenyl ether) was dissolved in 8.25mL of N-methylpyrrolidone BPPO and an equivalent of N- (2- (dimethylaminoethyl) -N, N, N-dimethyloctadecyl ammonium bromide was added1-octadecyl-1, 4-diazabicyclo [2.2.2]Octane-1-onium->Or N, N-dimethyloctadecylamine->Reacting for 48-72 h at normal temperature under stirring (the stirring rotating speed is 100 rpm) to obtain ionomer solutions such as viscous octadecyl hydrophobic long chain modified or tandem biscationic ionomers QPPO-TMEDA-C18 or QPPO-DABCO-C18 or tadpole ionomers QPPO-C18;
3) Preparing a composite film: taking 4g of the poly 2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain modified ionomer solution in the step (2), adding ethanol, and stirring uniformly. And (2) carrying out blade coating on the mixed solution in the step (1) to obtain a wet XEtOH QPPO < - > C18@PE film which is placed in parallel, heating the composite film at 40-60 ℃ for 48-72 h to slowly remove volatilization, along with the prolongation of heating time, continuously volatilizing the solvent, crystallizing and separating out QPT, continuously winding a hydrophobic long side chain around a polyethylene pore wall structure to obtain a dry film of X EtOH QPPO < - > C18@PE with good compatibility, and fully soaking the dry film in distilled water to obtain the ultra-thin microporous polyethylene reinforced composite anion exchange film X EtOH QPPO < - > C18@PE.
The substrate of the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane is an ultra-thin microporous polyethylene membrane with the aperture of 30-200 nm, the thickness of 9+/-2 mu m, the porosity of 45+/-5 percent and the mechanical properties: tensile strength 123.19MPa and elongation at break 157.45%.
The performance parameters of the ion exchange membranes, such as water absorption, swelling, ion selective permeability, sheet resistance, mechanical properties (tensile strength and elongation at break) and electrodialysis performance measurements in all examples of the invention and comparative examples were as described in main references B.Wei, J.Feng, C.Chen, S.Zhong, S.Liao, Y.Yu, X.Li, highly permselective tadpole-type ionic anion exchange membranes for electrodialysis desalination, journal of Membrane Science,600 (2020) 117861.
Determination of ion-selective permeabilities: the film samples were taken out after 6cm×9cm immersion in 0.5M sodium chloride solution for 48h for testing. The anion exchange membrane to be measured is fixed in the middle of the compartment, one end is added with 0.5M sodium chloride solution, the other end is added with 0.1M sodium chloride solution, and concentration polarization phenomenon is eliminated by intense stirring. The voltage across the membrane was measured with a silver/silver chloride-connected multimeter. The ion permselectivity P is calculated as follows:
Wherein E is measured Representing the film voltage obtained by the test, E theroetical Represents the theoretical membrane voltage.
Measurement of surface resistance: the test was performed in a home-made four-compartment device comprising two electrode compartments and two intermediate compartments using a constant current method. The film samples were taken out after 6cm×9cm immersion in 0.5M sodium chloride solution for 48h for testing. Respectively using 2 tabletsThe cation exchange membrane separates the electrode solution in the electrode chamber from the sodium chloride aqueous solution chamber. Is filled with 0.25M sodium sulfate solution, the intermediate chamber is filled with 0.5M sodium chloride solution, and an electrochemical workstation (IviemStat) is used to provide a constant current density (5 mA cm) -2 ). The resistance was tested with and without the anion exchange membrane to be tested. R of film to be measured m The calculation formula is as follows:
R m ＝R cell -R sol
wherein R is cell And R is sol The resistance tested with and without anion exchange membrane is shown, respectively.
Determination of water absorption and swelling Rate: the film samples were vacuum dried at 60℃for 48 hours at 3cm by 3cm, then immersed in deionized water at room temperature for 24 hours, rapidly wiped off the water on the film surface with filter paper, and the mass of the wet film was rapidly measured and the two-dimensional size of the wet film was measured. The water absorption WU and swelling SR of the ion exchange membrane are calculated as follows:
wherein W is wet Indicating the mass of the wet film, W dry Indicating the dry film mass, L wet Represents the length of the wet film L dry Indicating the length of the dry film.
Determination of tensile Strength: wet film samples were tested 5cm x 0.5cm using an Instron M3300 electronic universal tester with a film draw rate of 5mm/min.
Measurement of electrodialysis performance: the electrodialysis performance test is carried out in a self-made electrodialysis device which consists of a concentration chamber, a desalination chamber and two electrode chambers, wherein the effective membrane area is 20.25cm 2 And clamping the pretreated AEMs between a concentration chamber and a desalination chamber at the beginning of the test, respectively clamping 2 pieces of Nafion-115 between the concentration chamber, an electrode chamber, the desalination chamber and the electrode chamber, continuously pumping 200mL of 0.3M sodium sulfate solution into the electrode chamber of the electrodialysis cell by using a constant flow pump, and continuously circulating 338mL of 0.1M NaCl solution into the concentration chamber and the desalination chamber. The electrochemical workstation is utilized to continuously input current in a constant current mode and record corresponding voltage change values. The conductivity of the aqueous NaCl solution in the desalting chamber was recorded every 30min using a conductivity meter (Lei-ci DDS-307) for a period of 150min. Wherein the current density tested was 15mA cm -2 . The details of the calculation of the current efficiency η, the salt flux J and the energy consumption EC are as follows.
The current efficiency η is calculated as follows:
wherein Z represents the number of charges carried by chloride ions, C 0 And C t Respectively represents the concentration (M), V of sodium chloride solution in the dilution tank before and after the desalination test 0 And V t The volumes (L) of the sodium chloride solutions in the dilution tanks before and after the desalination test are respectively represented, N represents the number of repeating units in the desalination tank stack (n=1), I represents the current (a) of the desalination test, and t represents the test time (t=9000 s).
The energy consumption EC is calculated as follows:
wherein U represents the voltage variation value (V) in the electrodialysis desalination test process, M NaCl Represents the molar mass (M) NaCl ＝58.44g mol -1 ). The other symbols are as defined above.
The salt flux J is calculated as follows:
wherein A represents the effective membrane area (m -2 ) 2.025X 10 -3 m 2 The other symbols are as defined above.
Example 1
(1) Pretreatment of ultra-thin microporous polyethylene film
Ultra-thin microporous polyethylene substrates after ultrasonic treatment in ethanol (6 cm x 15cm,SK Innovatio company,
9+/-2 mu m) is placed on a horizontal glass plate, so that the glass plate is completely attached to the glass plate, and wrinkles are removed by spraying ethanol on the surface of polyethylene; wait for the ethanol on the polyethylene substrate to evaporate completely.
(2) Preparation of Poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic Long chain series biscationic ionomer (QPPO-TMEDA-C18) solution
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, then a quaternizing agent TMEDA-C18 (1.1195 g,2.49 mmol) was weighed and added to the BPPO solution, and the mixture was stirred at room temperature (stirring speed: 100 rpm) for 48 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain tandem biscationic ionomer (QPPO-TMEDA-C18) solution.
(3) Preparation of ultrathin microporous polyethylene reinforced anion exchange membrane 5% EtOH QPPO-TMEDA-C18@PE
4g of the solution of the poly (2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain tandem biscationic ionomer (QPPO-TMEDA-C18) in the step (2) is taken, and 5wt% (0.21 g) of ethanol is added to stir uniformly. And (3) uniformly scraping 3.1g of the mixed solution on the ultrathin microporous polyethylene film obtained in the step (1) to obtain a parallel-placed wet 5% EtOH QPPO-TMEDA-C18@PE film, wherein the dosage of the QPPO-TMEDA-C18 solution of each square centimeter polyethylene substrate film is 0.034g, heating the composite film at 60 ℃ for 48h to slowly remove volatilization, continuously volatilizing the solvent along with the prolongation of heating time, and continuously assembling the QPPO-TMEDA-C18 ionomer layer by mutually attracting the structure of the long hydrophobic side chain of the QPPO-TMEDA-C18 and the PE hole wall structure, so that the QPPO-TMEDA-C18 ionomer continuously gathers and assembles the PE hole wall layer by layer to separate out, further completing the filling of the holes and the covering of the surface layer, and fully soaking the dry film in distilled water to obtain the 5% EtOH QPPO-TMEDA-C18@PE film with good compatibility, wherein the thickness is 46 mu m.
The front and back scanning electron microscope characterization was performed on 5% EtOH QPPO-TMEDA-C18@PE, as shown in FIGS. 4 and 7, with no cracks on the film surface, relatively flat and uniform microstructure. FIG. 5 is a side elevational view of 5% EtOH QPPO-TMEDA-C18@PE illustrating the uniformity of the 5% EtOH QPPO-TMEDA-C18@PE structure and FIG. 6 is a further enlarged side elevational view further illustrating the uniformity of the microstructure without significant delamination from the microporous polyethylene.
The basic performance test result of the ultra-thin microporous polyethylene reinforced composite anion exchange membrane 5% EtOH QPPO-TMEDA-C18@PE is as follows: at room temperature, the water absorption rate is 10.90%, the swelling rate is 1.50%, the ion selective permeability is 95.00%, and the area resistance is 2.23 Ω cm 2 The tensile strength was 46.91MPa, and the elongation at break was 119.05%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%. The thickness of the 5% EtOH QPPO-TMEDA-C18@PE of this example was much less than that of the QPPO-TMEDA-C18 intrinsic film (96 microns) and commercial film AMX (125 microns) of comparative example 1, which was significantly superior to those of comparative example 1 in ion permselectivity, conductivity, and mechanical properties.
ED desalination performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 5% EtOH QPPO-TMEDA-C18@PE: current efficiency η= 94.43% (15 mA cm 2 ) Salt flux j= 85.89mg m -2 s -1 Energy consumption ec=1.64 kWh kg - 1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Can be used forConsumption ec=2.12 kWh kg -1 NaCl. ED desalination performance of 5% EtOH QPPO-TMEDA-C18@PE was significantly better than AMX and QPPO-TMEDA-C18 of comparative example 1. The 5% EtOH QPPO-TMEDA-C18@PE has certain capability of taking the ion selective permeability, the conductivity and the mechanical property into account, and good ED desalting performance is obtained.
Example 2
(1) Pretreatment of ultra-thin microporous polyethylene film
Placing an ultrathin microporous polyethylene substrate (6 cm multiplied by 15 cm) subjected to ultrasonic treatment in ethanol on a horizontal glass plate, completely attaching the ultrathin microporous polyethylene substrate to the glass plate, and removing wrinkles by spraying ethanol on the surface of the polyethylene; wait for the ethanol on the polyethylene substrate to evaporate completely.
(2) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-TMEDA-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, then a quaternizing agent TMEDA-C18 (1.1195 g,2.49 mmol) was weighed and added to the BPPO solution, and the mixture was stirred at room temperature (stirring speed: 100 rpm) for 48 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-TMEDA-C18 solution.
(3) Preparation of ultrathin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-TMEDA-C18@PE
4g of the solution of the 2, 6-dimethyl phenyl ether octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-TMEDA-C18 in the step (2) is taken, and 15wt% (0.71 g) of ethanol is added to stir uniformly. And (3) spreading 3.1g of the mixed solution on the step (1) to obtain a wet 15% EtOH QPPO-TMEDA-C18@PE film which is placed in parallel, wherein the dosage of the QPPO-TMEDA-C18 solution of each square centimeter polyethylene matrix film is 0.034g, heating the composite film at 60 ℃ for 48h to slowly volatilize, continuously volatilizing the solvent along with the prolongation of heating time, and continuously gathering and separating the hydrophobic long side chain of the QPPO-TMEDA-C18 and the PE hole wall structure due to structural similarity, so that the QPPO-TMEDA-C18 ionomer continuously gathers and assembles the PE hole wall to layer by layer to be deposited and separated out, further completing the hole filling and the surface layer covering, and fully soaking the dry film in distilled water to obtain the 15% EtOH QPPO-TMEDA-C18@PE film with good compatibility, thereby obtaining the ultra-thin microporous polyethylene reinforced composite anion exchange film with the thickness of 32 mu m.
The front and back scanning electron microscope characterization was performed on 15% EtOH QPPO-TMEDA-C18@PE, as shown in FIGS. 8, 11, with no cracks on the film surface, relatively flat and uniform microstructure. FIG. 9 is a side elevational view of 15% EtOH QPPO-TMEDA-C18@PE illustrating the uniformity of 15% EtOH QPPO-TMEDA-C18@PE structure and FIG. 10 is a further enlarged side view further illustrating the uniformity of microstructure without significant delamination from the microporous polyethylene.
Basic performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-TMEDA-C18@PE: at room temperature, the water absorption rate is 7.85%, the swelling rate is 1.41%, the ion selective permeability is 96.32%, and the area resistance is 1.33 Ω cm 2 The tensile strength was 58.56MPa, and the elongation at break was 132.42%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%. The 15% EtOH QPPO-TMEDA-C18@PE was much smaller in thickness than the QPPO-TMEDA-C18 intrinsic film (96 microns) and commercial film AMX (125 microns) of comparative example 1, which was significantly better in ion selective permeability, conductivity, and mechanical properties than the QPPO-TMEDA-C18 intrinsic film and commercial film AMX of comparative example 1.
ED desalination performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-TMEDA-C18@PE: current efficiency η= 94.07% (15 mA cm 2 ) Salt flux j= 85.55mg m -2 s -1 Energy consumption ec=1.50 kWh kg - 1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Energy consumption ec=2.12 kWh kg -1 NaCl. ED desalination performance of 15% EtOH QPPO-TMEDA-C18@PE is obviously better than that of AMX and QPPO-TMEDA-C18 intrinsic film of comparative example 1, which shows that 15% EtOH QPPO-TMEDA-C18@PE has good ion selective permeability, conductivity and mechanical propertyED desalination performance.
Example 3
(1) Pretreatment of ultra-thin microporous polyethylene film
Placing an ultrathin microporous polyethylene substrate (6 cm multiplied by 15 cm) subjected to ultrasonic treatment in ethanol on a horizontal glass plate, completely attaching the ultrathin microporous polyethylene substrate to the glass plate, and removing wrinkles by spraying ethanol on the surface of the polyethylene; wait for the ethanol on the polyethylene substrate to evaporate completely.
(2) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-TMEDA-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, then a quaternizing agent TMEDA-C18 (1.1195 g,2.49 mmol) was weighed and added to the BPPO solution, and the mixture was stirred at room temperature (stirring speed: 100 rpm) for 48 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-TMEDA-C18 solution.
(3) Preparation of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 25% EtOH QPPO-TMEDA-C18@PE
Taking 4g of the solution of the 2, 6-dimethyl phenyl ether octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-TMEDA-C18 in the step (2), adding 25wt% (1.33 g) of ethanol, and stirring uniformly. And (3) spreading 3.1g of the mixed solution on the step (1) to obtain a wet 25% EtOH QPPO-TMEDA-C18@PE film which is placed in parallel, wherein the dosage of the QPPO-TMEDA-C18 solution of each square centimeter polyethylene matrix film is 0.034g, heating the composite film at 60 ℃ for 48h to slowly volatilize, continuously volatilizing the solvent along with the prolongation of heating time, and continuously gathering and separating the hydrophobic long side chain of the QPPO-TMEDA-C18 and the PE hole wall structure due to structural similarity, so that the QPPO-TMEDA-C18 ionomer continuously gathers and assembles the PE hole wall to layer by layer to be deposited and separated out, further completing the filling of the hole and the covering of the surface layer, and fully soaking the dry film in distilled water to obtain the 25% EtOH QPPO-TMEDA-C18@PE film with good compatibility, thereby obtaining the ultra-thin microporous polyethylene reinforced composite anion exchange film with the thickness of 22 mu m.
The front and back scanning electron microscope characterization was performed on 25% EtOH QPPO-TMEDA-C18@PE, as shown in FIGS. 12, 15, with no cracks on the film surface, relatively flat and uniform microstructure. FIG. 13 is a side elevational view of 25% EtOH QPPO-TMEDA-C18@PE, illustrating the uniformity of 25% EtOH QPPO-TMEDA-C18@PE structure, and FIG. 14 is a further enlarged side elevational view, further illustrating the uniformity of microstructure, no significant delamination from microporous PE, and little 30-65nm "defect" occurred, but no effect on overall structural integrity.
Basic performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 25% EtOH QPPO-TMEDA-C18@PE: at room temperature, the water absorption rate is 5.44%, the swelling rate is 1.40%, the ion selective permeability is 93.68%, and the area resistance is 1.53 Ω cm 2 The tensile strength was 62.19MPa, and the elongation at break was 141.33%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%. The thickness of 25% EtOH QPPO-TMEDA-C18@PE is much smaller than that of the QPPO-TMEDA-C18 intrinsic film (96 microns) and the commercial film AMX (125 microns) of comparative example 1, and the ion selective permeability, conductivity and mechanical properties are significantly better than those of the QPPO-TMEDA-C18 intrinsic film and the commercial film AMX of comparative example 1.
ED desalination performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 25% EtOH QPPO-TMEDA-C18@PE: current efficiency η= 91.34% (15 mA cm 2 ) Salt flux j=83.08 mg m -2 s -1 Energy consumption ec=2.20 kWh kg - 1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Energy consumption ec=2.12 kWh kg -1 NaCl. The ED desalination performance of 25% EtOH QPPO-TMEDA-C18@PE is superior to that of AMX and the QPPO-TMEDA-C18 intrinsic film of comparative example 1, which shows that 25% EtOH QPPO-TMEDA-C18@PE has good ED desalination performance due to better compromise of ion selective permeability, conductivity and mechanical properties.
In the following comparative examples, 4g of the poly (2, 6-dimethyl phenyl octadecyl) hydrophobic long chain modified ionic ionomer solution in the step (2) was poured onto a clean and flat glass plate, and heated at 40℃to 60℃for 48 hours to 72 hours to allow the solvent to evaporate sufficiently, to prepare comparative examples 1QPPO-TMEDA-C18, comparative example 2QPPO-DABCO-C18 and comparative example 3QPPO-C18 anion exchange membranes. And stripping with deionized water to obtain yellow transparent films QPPO-TMEDA-C18, QPPO-DABCO-C18 and QPPO-C18.
Comparative example 1
(1) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-TMEDA-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, then the quaternizing agent TMEDA-C18 (1.1195 g,2.49 mmol) was weighed and added to the BPPO solution, and stirred at room temperature (stirring speed was 100 rpm) for 48 hours to obtain a viscous poly 2, 6-dimethyl phenyl ether octadecyl hydrophobic long chain tandem biscationic ionomer solution.
(2) Preparation of intrinsic anion exchange membrane QPPO-TMEDA-C18
4g of the solution of the 2, 6-dimethyl phenyl ether octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-TMEDA-C18 in the step (1) is poured on a clean and flat glass plate, and the solution is heated at 60 ℃ for 48 hours to fully volatilize the solvent. After stripping with deionized water, a yellow transparent film QPPO-TMEDA-C18 was obtained, with a thickness of 96. Mu.m.
The QPPO-TMEDA-C18 was front-side and back-side scanning electron microscopy characterized as shown in fig. 16, 19, the film surface was crack-free, relatively flat and microstructure uniform. FIG. 17 is a side elevational view of QPPO-TMEDA-C18 illustrating the uniformity of the QPPO-TMEDA-C18 structure, and FIG. 18 is a further enlarged side view illustrating the uniformity of the microstructure. The transmission electron microscope of QPPO-TMEDA-C18 is shown in figure 20, the dark part represents hydrophilic phase, the bright part represents hydrophobic phase, and thus the QPT hydrophilic-hydrophobic microphase separation structure is obvious, and the prepared anion exchange membrane has microphase separation structure is proved.
Basic properties of intrinsic anion exchange membrane QPPO-TMEDA-C18: at room temperature, the water absorption rate is 8.42%, the swelling rate is 6.96%, the ion selective permeability is 89.20%, and the area resistance is 3.22 Ω cm 2 The tensile strength was 13.28MPa, and the elongation at break was 24.58%. Commercial products Basic performance of industrial film AMX (astm japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%. The basic performance of QPPO-TMEDA-C18 is very close to that of commercial membrane AMX, and can be used as ionomer material of common AEMs.
ED desalination Performance of QPPO-TMEDA-C18: current efficiency η=89.50% (15 mA cm 2 ) Salt flux j=80.40 mg m -2 s -1 Energy consumption ec=2.21 kWh kg -1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Energy consumption ec=2.12 kWh kg -1 NaCl. ED desalination performance of QPPO-TMEDA-C18 was superior to AMX, demonstrating that QPPO-TMEDA-C18 produced better ED desalination performance than fiber-reinforced commercial membrane AMX due to uniform intrinsic structure and better anion conductivity and ion-passing selectivity.
Example 4
(1) Pretreatment of ultra-thin microporous polyethylene film
Placing an ultrathin microporous polyethylene substrate (6 cm multiplied by 15 cm) subjected to ultrasonic treatment in ethanol on a horizontal glass plate, completely attaching the ultrathin microporous polyethylene substrate to the glass plate, and removing wrinkles by spraying ethanol on the surface of the polyethylene; wait for the ethanol on the polyethylene substrate to evaporate completely.
(2) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-DABCO-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, and then a quaternizing agent DABCO-C18 (1.1090 g,2.49 mmol) was weighed and added to the BPPO solution, and the mixture was stirred at room temperature (stirring speed: 100 rpm) for reaction for 72 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer solution QPPO-DABCO-C18.
(3) Preparation of ultrathin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-DABCO-C18@PE
4g of the solution of the poly (2, 6-dimethyl phenyl ether octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-DBBCO-C18 in the step (2) is taken, and then 15wt% (0.71 g) of ethanol is added to stir uniformly. And (3) spreading 3.1g of the mixed solution on the step (1) to obtain a wet 15% EtOH QPPO-DABCO-C18@PE film which is placed in parallel, wherein the dosage of the QPPO-DABCO-C18 solution of each square centimeter polyethylene matrix film is 0.034g, heating the composite film at 40 ℃ for 72h to slowly volatilize, continuously volatilizing the solvent along with the prolongation of heating time, and continuously gathering and assembling the QPPO-DABCO-C18 ionomer on the PE pore wall due to the mutual attraction generated by the structural similarity between the hydrophobic long side chain of the QPPO-DABCO-C18 and the PE pore wall structure, so that the filling of the pores and the covering of the surface layer are completed, and the dry film is fully soaked in distilled water to obtain the 15% EtOH QPPO-DABCO-C18@PE film with the thickness of 34 mu m.
Basic performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-DABCO-C18@PE: at room temperature, the water absorption rate is 7.50%, the swelling rate is 1.38%, the ion selective permeability is 97.04%, and the area resistance is 1.56 Ω cm 2 The tensile strength was 46.33MPa, and the elongation at break was 120.42%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%. The 15% EtOH QPPO-DABCO-C18@PE was much thinner than the QPPO-TMEDA-C18 intrinsic film (150 microns) and commercial film AMX (125 microns) of comparative example 2, which was significantly superior to the QPPO-DABCO-C18 intrinsic film and commercial film AMX of comparative example 2 in ion permselectivity, conductivity, and mechanical properties.
ED desalination performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-DABCO-C18@PE: current efficiency η=95.02% (15 mA cm 2 ) Salt flux j= 86.41mg m -2 s -1 Energy consumption ec=1.56 kWh kg - 1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Energy consumption ec=2.12 kWh kg -1 NaCl. The ED desalination performance of 15% EtOH QPPO-DABCO-C18@PE is obviously superior to that of AMX and the QPPO-TMEDA-C18 intrinsic film of comparative example 2, which shows that 15% EtOH QPPO-DABCO-C18@PE has good ED desalination performance due to the combination of ion selective permeability, conductivity and mechanical properties.
Comparative example 2
(1) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer QPPO-DABCO-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,2.49 mmol-CH) having a bromomethylation degree of 0.40 2 Br) was completely dissolved in 8.25mL of NMP, and then a quaternizing agent DABCO-C18 (1.1090 g,2.49 mmol) was weighed and added to the BPPO solution, and the mixture was stirred at room temperature (stirring speed: 100 rpm) for reaction for 72 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tandem biscationic ionomer solution QPPO-DABCO-C18.
(2) Preparation of intrinsic anion exchange membrane QPPO-DABCO-C18
4g of the solution of the 2, 6-dimethyl phenyl ether octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-DABCO-C18 in the step (1) is poured on a clean and flat glass plate, and the solution is heated for 72 hours at 40 ℃ to fully volatilize the solvent. The yellow transparent film QPPO-DABCO-C18 with the thickness of 150 μm is obtained after the deionized water is stripped.
QPPO-DABCO-C18 is fragile and cannot be tested for electrical and mechanical properties.
Example 5
(1) Pretreatment of ultra-thin microporous polyethylene film
Placing an ultrathin microporous polyethylene substrate (6 cm multiplied by 15 cm) subjected to ultrasonic treatment in ethanol on a horizontal glass plate, completely attaching the ultrathin microporous polyethylene substrate to the glass plate, and removing wrinkles by spraying ethanol on the surface of the polyethylene; wait for the ethanol on the polyethylene substrate to evaporate completely.
(2) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long-chain modified tadpole type ionomer QPPO-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,3.50 mmol-CH) having a bromomethylation degree of 0.57 2 Br) was completely dissolved in 8.25mL NMP, followed by weighing the quaternizing agent N, N-dimethylOctadecylamine(1.0430 g,3.50 mmol) was added to the BPPO solution and stirred at room temperature (stirring speed: 100 rpm) for 48 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tadpole ionomer solution QPPO-C18.
(3) Preparation of ultrathin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-C18@PE
4g of the 2, 6-dimethyl phenyl octadecyl hydrophobic long-chain tadpole ionomer solution QPPO-C18 solution obtained in the step (2) is taken, and then 15wt% (0.71 g) of ethanol is added to the solution for stirring uniformly. And (3) spreading 3.1g of the mixed solution on the step (1) to obtain a wet 15% EtOH QPPO-C18@PE film which is placed in parallel, wherein the dosage of the QPPO-C18 solution of each square centimeter of polyethylene matrix film is 0.034g, heating the composite film at 60 ℃ for 48h to slowly remove volatilization, and along with the prolongation of heating time, the solvent continuously volatilizes, so that the hydrophobic long side chains of the QPPO-C18 and the PE hole wall structure are mutually attracted due to structural similarity, the QPPO-C18 ionomer is continuously gathered and assembled on the PE hole wall layer by layer to deposit and separate out, further the filling of holes and the covering of the surface layer are completed, and the 15% EtOH QPPO-C18@PE dry film with good compatibility is obtained, and the dry film is fully soaked in distilled water, so that the 15% EtOH QPPO-C18@PE of the ultra-thin microporous polyethylene reinforced composite anion exchange film is obtained with the thickness of 33 mu m.
Basic performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-C18@PE: at room temperature, the water absorption rate is 6.85%, the swelling rate is 1.61%, the ion selective permeability is 97.32%, and the area resistance is 1.60 Ω cm 2 The tensile strength was 55.56MPa, and the elongation at break was 130.42%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 The tensile strength was 35.07MPa, and the elongation at break was 21.32%.15% EtOH QPPO-C18@PE is much thinner than the QPPO-C18 intrinsic film (85 microns) and commercial film AMX (125 microns) of comparative example 3, and has significantly better ion permselectivity, conductivity, and mechanical properties than the QPPO-C18 film of comparative example 3Intrinsic and commercial films AMX.
ED desalination performance of ultra-thin microporous polyethylene reinforced composite anion exchange membrane 15% EtOH QPPO-C18@PE: current efficiency η= 95.29% (15 mA cm 2 ) Salt flux j= 86.66mg m -2 s -1 Energy consumption ec=1.56 kWh kg -1 NaCl. ED desalination performance of 15% EtOH QPPO-C18@PE is obviously superior to that of AMX and comparative example 1 intrinsic film QPPO-TMEDA-C18, which shows that 15% EtOH QPPO-C18@PE has the characteristics of ion selective permeability, conductivity and mechanical property.
Comparative example 3
(1) Preparation of poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long-chain tandem biscationic ionomer QPPO-C18
Brominated poly (2, 6-dimethylphenyl) ether BPPO (1.0 g,3.50 mmol-CH) having a bromomethylation degree of 0.57 2 Br) was completely dissolved in 8.25mL NMP, followed by weighing the quaternizing agent N, N-dimethyloctadecylamine(1.0430 g,3.50 mmol) was added to the BPPO solution and stirred at room temperature (stirring speed: 100 rpm) for 48 hours to obtain a viscous poly (2, 6-dimethyl phenyl ether) octadecyl hydrophobic long chain tadpole ionomer solution QPPO-C18.
(2) Preparation of intrinsic anion exchange Membrane QPPO-C18
4g of the 2, 6-dimethyl phenyl octadecyl hydrophobic long-chain tadpole ionomer solution QPPO-C18 solution in the step (1) is poured on a clean and flat glass plate, and the solution is heated for 48 hours at 60 ℃ to fully volatilize the solvent. The yellow transparent film QPPO-C18 with the thickness of 85 μm is obtained after the deionized water is stripped.
Basic properties of QPPO-C18: at room temperature, the water absorption rate is 13.50%, the swelling rate is 3.80%, the ion selective permeability is 94.60%, and the area resistance is 2.78 Ω cm 2 The tensile strength was 13.80MPa, and the elongation at break was 13.30%. Basic properties of commercial film AMX (astm in japan): at room temperature, the water absorption rate is 24.93%, the swelling rate is 5.32%, the ion selective permeability is 91.0%, and the area resistance is 3.12 Ω cm 2 Tensile strength of 35.07MPa and elongation at break of21.32％。
ED desalination Performance of QPP-C18: current efficiency η= 87.33% (15 mA cm 2 ) Salt flux j=79.35 mg m - 2 s -1 Energy consumption ec=1.80 kWh kg -1 NaCl. ED desalination performance of astm commercial film AMX in japan: current efficiency η= 83.45%, salt flux j= 75.82mg m -2 s -1 Energy consumption ec=2.12 kWh kg -1 NaCl. The ED desalination performance of QPPO-C18 is superior to AMX, indicating that QPPO-TMEDA-C18, due to the homogeneous intrinsic structure and better anion conductivity and ion-passing selectivity, produces ED desalination performance superior to fiber-reinforced commercial membrane AMX, which can be used as ionomer matrix material for high performance composite AEMs.
The ionomer material of the composite anion exchange membrane is octadecyl hydrophobic long-chain modified tadpole type polyphenyl ether ionomer QPPO-C18, and serially connected double-cation polyphenyl ether ionomers QPPO-TMEDA-C18 and QPPO-DABCO-C18, and the matrix is an ultrathin microporous PE membrane. The above examples change the surface properties of the substrate by treating the substrate ultra-thin microporous polyethylene film with ethanol, and additionally, the substrate is treated with brominated polyphenylene ether having a bromination degree of 0.40 to 0.60 and ionization reagents TMEDA-C18, DABCO-C18 and N, N-dimethyloctadecylamine equivalent 1: and 1, reacting for 48-72 h at room temperature to obtain an ionomer body. The embodiment is that 5 to 25 percent of ethanol is added into a certain mass of 20 weight percent ionomer solution, the property of the ionomer solution is changed, and then the ionomer is deposited and aggregated on a substrate in the film preparation process at the temperature of 40 to 60 ℃ is debugged, so that a series of ultrathin composite anion exchange films with high ion selectivity, low surface resistance and high mechanical property are obtained. The comparative example was one in which a mass of 20wt% ionomer solution was volatilized at the same film forming temperature. Under the same conditions, the basic performance and electrodialysis performance of the composite anion exchange membrane, the ionomer intrinsic membrane and the commercial membrane are tested, and test results show that the embodiment of the invention can not only maintain the local high cationic charge density of the ionomer intrinsic structure, but also modify the microphase structure of the ionomer in the hole by utilizing the strong interaction of the flexible hydrophobic long side chain and the polyethylene hole wall so as to further improve the ion selective permeability of the composite membrane, and further reduce the membrane by means of matrix enhancement The thickness of the composite film (the thickness of the composite film is 20-50 micrometers, which is obviously smaller than that of commercial films and ionomer intrinsic films), so that the film resistance of the composite film is reduced, and the conductivity and mechanical property of the composite film are synchronously enhanced. The basic properties of the ultrathin high-performance composite anion exchange membrane obtained in the example above at room temperature are as follows: the water absorption rate is 5.44 to 10.90 percent, the swelling rate is 1.38 to 1.61 percent, the ion selective permeability is 93.68 to 97.32 percent, and the surface resistance is 1.33 ohm cm 2 ～2.23Ωcm 2 Mechanical properties: the tensile strength is 46.33 MPa-62.19 MPa, and the elongation at break is 119.05-141.33%. 0.1M NaCl solution system, 15mA cm -2 The electrodialysis desalination performance of the high-performance composite anion exchange membrane is as follows: the current efficiency is 91.34-95.29%, and the flux is 83.08mg m -2 s -1 ～86.66mg m -2 s -1 The energy consumption is 1.50kWh kg -1 NaCl～2.20kWh kg -1 NaCl, is superior to the commercial film AMX of Japanese ASTOM under the same conditions. ED desalination performance of AMX: the current efficiency is 83.45%, and the salt flux is 75.82mg m -2 s -1 The energy consumption is 2.12 kWh kg -1 NaCl. The invention effectively solves the problem that the existing anion exchange membrane can not achieve high ion permeation selectivity, low surface resistance and high mechanical property, and the developed ultrathin high-performance anion exchange membrane meets the requirements of comprehensive properties such as high current efficiency, salt flux, low energy consumption and the like of desalination electrodialysis, and has good application prospect.
The invention obtains the basic performances of the ethanol-assisted ultrathin microporous polyethylene composite anion exchange membrane X EtOH QPPO-TMEDA-C18@PE, X EtOH QPPO-DABCO-C18@PE and X EtOH QPPO-C18@PE: the water absorption rate at room temperature is 5.44 to 10.90 percent, the swelling rate is 1.38 to 1.61 percent, the ion selective permeability is 93.68 to 97.32 percent, and the surface resistance is 1.33 ohm cm 2 ～2.23Ωcm 2 Mechanical properties: the tensile strength is 46.33 MPa-62.19 MPa, and the elongation at break is 119.05-141.33%.
It should be noted that, the protection scope of the present invention is not limited by the above embodiments, and any equivalent changes, modifications or evolution made by those skilled in the art to the above embodiments by using the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.
Claims (10)
1. The ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane is characterized in that an ionomer solution is uniformly mixed with ethanol and then coated on the ultra-thin microporous polyethylene membrane, a dry film is obtained after volatile matters are removed, and the dry film is fully soaked in distilled water to obtain the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane; the ionomer is QPPO-TMEDA-C18, QPPO-DABCO-C18 or QPPO-C18; the structural formula is as follows:
2. the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane according to claim 1, wherein the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane has a thickness of 20-50 μm, a water absorption of 5.44-10.90%, a swelling ratio of 1.38-1.61%, an ion selective permeability of 93.68-97.32%, and a sheet resistance of 1.33 Ω cm 2 ～2.23Ωcm 2 The tensile strength is 46.33 MPa-62.19 MPa, and the elongation at break is 119.05-141.33%.
3. The method for preparing the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane as claimed in claim 1 or 2, which is characterized by comprising the following steps:
1) Pretreatment of a substrate: placing the ultrathin microporous polyethylene film on a glass plate after cleaning, completely attaching the ultrathin microporous polyethylene film with the glass plate, spraying ethanol on the surface of the ultrathin microporous polyethylene film until the film is naturally flattened, and naturally volatilizing at room temperature until the surface is dry;
2) Ionomer solution preparation: dissolving brominated poly 2, 6-dimethyl ether in N-methylpyrrolidone, adding N- (2- (dimethylaminoethyl) -N, N, N-dimethyl octadecyl ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-ium or N, N-dimethyl octadecyl amine, and reacting at normal temperature for 48-72 h under stirring to obtain QPPO-TMEDA-C18, QPPO-DABCO-C18 or QPPO-C18 ionomer solution respectively;
3) Preparing a composite film: mixing the ionomer solution obtained in the step 2) with ethanol, coating the mixture on the treated ultrathin microporous polyethylene film, removing volatile components from the composite film at 40-60 ℃ to obtain a dry film, and fully soaking the dry film in distilled water to obtain the ultrathin high-performance composite anion exchange film.
4. The method for preparing the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane according to claim 3, wherein in the step (1), the ultra-thin microporous polyethylene membrane is completely immersed in ethanol for ultrasonic cleaning for 2-5 times.
5. The method for preparing an ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane according to claim 3, wherein in the step (2), the bromomethylation degree of the brominated poly (2, 6-dimethyl-phenyl ether) is 0.4-0.6.
6. The method for preparing an ultra-thin microporous polyethylene reinforced high-performance composite anion-exchange membrane according to claim 3, wherein in the step (2), the molar ratio of bromomethyl group of brominated poly 2, 6-dimethyl-phenyl-ether to N- (2- (dimethylaminoethyl) -N, N, N-dimethyloctadecyl-ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-onium or N, N-dimethyloctadecyl-amine is 1:1, the concentration of bromomethyl group of brominated poly 2, 6-dimethyl-phenyl-ether to N- (2- (dimethylaminoethyl) -N, N, N-dimethyloctadecyl-ammonium bromide, 1-octadecyl-1, 4-diazabicyclo [2.2.2] octane-1-onium or N, N-dimethyloctadecyl-amine is 20-30wt%, and the stirring speed is 100 rpm-200 rpm.
7. The method for preparing an ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane according to claim 3, wherein in the step (3), the addition amount of ethanol in the mixture of the ionomer solution and ethanol is 5-25 wt%.
8. The method for preparing the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane according to claim 3, wherein in the step (3), the mass of the ionomer solution coated on each square centimeter of the ultra-thin microporous polyethylene membrane is 0.027g-0.034g, and the volatile matter removal is realized by heating at 40-60 ℃ for 48-72 h.
9. Use of an ultra-thin microporous polyethylene reinforced high performance composite anion exchange membrane according to claim 1 or 2 in brine electrodialysis desalination.
10. The use of an ultra-thin microporous polyethylene reinforced high performance composite anion exchange membrane according to claim 9 in brine electrodialysis desalination; the method is characterized in that the current efficiency of the ultra-thin microporous polyethylene reinforced high-performance composite anion exchange membrane in brine electrodialysis desalination is 91.34-95.29%, and the flux is 83.08mg m -2 s -1 ～86.66mg m -2 s -1 The energy consumption is 1.50kWh kg -1 NaCl～2.20kWh kg -1 NaCl。
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