CN112546872B - Preparation method of monovalent selective cation exchange membrane - Google Patents
Preparation method of monovalent selective cation exchange membrane Download PDFInfo
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- CN112546872B CN112546872B CN202011633888.4A CN202011633888A CN112546872B CN 112546872 B CN112546872 B CN 112546872B CN 202011633888 A CN202011633888 A CN 202011633888A CN 112546872 B CN112546872 B CN 112546872B
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- 239000012528 membrane Substances 0.000 title claims abstract description 297
- 238000005341 cation exchange Methods 0.000 title claims abstract description 84
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- WRHZVMBBRYBTKZ-UHFFFAOYSA-N pyrrole-2-carboxylic acid Chemical compound OC(=O)C1=CC=CN1 WRHZVMBBRYBTKZ-UHFFFAOYSA-N 0.000 claims abstract description 70
- 238000002791 soaking Methods 0.000 claims abstract description 64
- 238000005406 washing Methods 0.000 claims abstract description 40
- 239000000243 solution Substances 0.000 claims abstract description 39
- DOYOPBSXEIZLRE-UHFFFAOYSA-N pyrrole-3-carboxylic acid Natural products OC(=O)C=1C=CNC=1 DOYOPBSXEIZLRE-UHFFFAOYSA-N 0.000 claims abstract description 35
- ZRZHXNCATOYMJH-UHFFFAOYSA-N 1-(chloromethyl)-4-ethenylbenzene Chemical compound ClCC1=CC=C(C=C)C=C1 ZRZHXNCATOYMJH-UHFFFAOYSA-N 0.000 claims abstract description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000007864 aqueous solution Substances 0.000 claims abstract description 27
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000012719 thermal polymerization Methods 0.000 claims abstract description 22
- PRAMZQXXPOLCIY-UHFFFAOYSA-N 2-(2-methylprop-2-enoyloxy)ethanesulfonic acid Chemical compound CC(=C)C(=O)OCCS(O)(=O)=O PRAMZQXXPOLCIY-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 239000011259 mixed solution Substances 0.000 claims abstract description 15
- UEEJHVSXFDXPFK-UHFFFAOYSA-N N-dimethylaminoethanol Chemical compound CN(C)CCO UEEJHVSXFDXPFK-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000007800 oxidant agent Substances 0.000 claims abstract description 10
- 230000001590 oxidative effect Effects 0.000 claims abstract description 10
- 239000002253 acid Substances 0.000 claims abstract description 9
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 claims description 62
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 21
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims description 20
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical group Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 11
- 238000002156 mixing Methods 0.000 claims description 8
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 4
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims description 2
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims description 2
- 238000006116 polymerization reaction Methods 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 210000004379 membrane Anatomy 0.000 description 204
- 238000005303 weighing Methods 0.000 description 34
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 33
- 239000002585 base Substances 0.000 description 31
- 238000003756 stirring Methods 0.000 description 27
- 150000001768 cations Chemical class 0.000 description 26
- NQXWGWZJXJUMQB-UHFFFAOYSA-K iron trichloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].Cl[Fe+]Cl NQXWGWZJXJUMQB-UHFFFAOYSA-K 0.000 description 21
- 150000002500 ions Chemical class 0.000 description 19
- -1 persulfate ions Chemical class 0.000 description 19
- 235000002639 sodium chloride Nutrition 0.000 description 18
- 239000011780 sodium chloride Substances 0.000 description 17
- 238000003760 magnetic stirring Methods 0.000 description 16
- 229920000139 polyethylene terephthalate Polymers 0.000 description 16
- 239000005020 polyethylene terephthalate Substances 0.000 description 16
- 238000001816 cooling Methods 0.000 description 14
- 239000008367 deionised water Substances 0.000 description 14
- 229910021641 deionized water Inorganic materials 0.000 description 14
- 238000000909 electrodialysis Methods 0.000 description 14
- 239000003014 ion exchange membrane Substances 0.000 description 14
- 238000012360 testing method Methods 0.000 description 13
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 12
- 238000000926 separation method Methods 0.000 description 12
- 229910001415 sodium ion Inorganic materials 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 7
- 229910001424 calcium ion Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 6
- 235000019341 magnesium sulphate Nutrition 0.000 description 6
- 230000005012 migration Effects 0.000 description 6
- 238000013508 migration Methods 0.000 description 6
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 5
- 150000001450 anions Chemical class 0.000 description 5
- 238000005342 ion exchange Methods 0.000 description 5
- 229920000867 polyelectrolyte Polymers 0.000 description 5
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 4
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- 238000004132 cross linking Methods 0.000 description 4
- 239000008151 electrolyte solution Substances 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000035699 permeability Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000013535 sea water Substances 0.000 description 4
- 229910052938 sodium sulfate Inorganic materials 0.000 description 4
- 235000011152 sodium sulphate Nutrition 0.000 description 4
- 125000000542 sulfonic acid group Chemical group 0.000 description 4
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 3
- 229920001940 conductive polymer Polymers 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000037230 mobility Effects 0.000 description 3
- 229920000128 polypyrrole Polymers 0.000 description 3
- 229920001661 Chitosan Polymers 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 238000010612 desalination reaction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229920000767 polyaniline Polymers 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 description 2
- 238000013341 scale-up Methods 0.000 description 2
- FYSNRJHAOHDILO-UHFFFAOYSA-N thionyl chloride Chemical compound ClS(Cl)=O FYSNRJHAOHDILO-UHFFFAOYSA-N 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000004971 Cross linker Substances 0.000 description 1
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical group OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 150000001448 anilines Chemical class 0.000 description 1
- 125000002490 anilino group Chemical group [H]N(*)C1=C([H])C([H])=C([H])C([H])=C1[H] 0.000 description 1
- 238000005349 anion exchange Methods 0.000 description 1
- 210000002469 basement membrane Anatomy 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229940075397 calomel Drugs 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 125000002843 carboxylic acid group Chemical group 0.000 description 1
- 239000003729 cation exchange resin Substances 0.000 description 1
- 229940023913 cation exchange resins Drugs 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 125000004218 chloromethyl group Chemical group [H]C([H])(Cl)* 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical compound Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- 230000007646 directional migration Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- FJKROLUGYXJWQN-UHFFFAOYSA-N papa-hydroxy-benzoic acid Natural products OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 229920001197 polyacetylene Polymers 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920000123 polythiophene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 238000005956 quaternization reaction Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 229960004889 salicylic acid Drugs 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 229940087596 sodium phenolsulfonate Drugs 0.000 description 1
- BLXAGSNYHSQSRC-UHFFFAOYSA-M sodium;2-hydroxybenzenesulfonate Chemical compound [Na+].OC1=CC=CC=C1S([O-])(=O)=O BLXAGSNYHSQSRC-UHFFFAOYSA-M 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 238000006277 sulfonation reaction Methods 0.000 description 1
- 125000000472 sulfonyl group Chemical group *S(*)(=O)=O 0.000 description 1
- YBBRCQOCSYXUOC-UHFFFAOYSA-N sulfuryl dichloride Chemical group ClS(Cl)(=O)=O YBBRCQOCSYXUOC-UHFFFAOYSA-N 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0093—Chemical modification
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/26—Electrical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/42—Ion-exchange membranes
-
- 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
Abstract
The invention discloses a preparation method of a monovalent selective cation exchange membrane, which comprises the following steps: (1) Soaking a cation exchange membrane serving as a base membrane in an oxidant aqueous solution, (2) soaking the membrane obtained in the step (1) in an ethanol solution of pyrrole-2-carboxylic acid to polymerize the pyrrole-2-carboxylic acid in the membrane and on the surface of the membrane; (3) Carrying out acid washing and then water washing on the membrane obtained in the step (2), and carrying out heating treatment after water washing; (4) Soaking the membrane obtained in the step (3) in a mixed solution containing p-chloromethyl styrene and 2-sulfoethyl methacrylate for a short time, taking out the membrane, clamping the membrane between two inert sheets, and then carrying out thermal polymerization treatment, and (5) soaking the membrane obtained in the step (4) in an N, N-dimethylethanolamine aqueous solution, and washing after soaking to obtain the monovalent selective cation exchange membrane.
Description
Technical Field
The invention relates to a preparation method of an ion exchange membrane, in particular to a preparation method of a monovalent selective cation exchange membrane.
Background
Electrodialysis is the process of separating, purifying and concentrating electrolyte solution by utilizing the selective permeability of ion exchange membranes to anions and cations and by the directional migration of the anions and cations under the action of an electric field. Its most basic use is for desalination and concentration of aqueous solutions. Electrodialysis is an electrically driven membrane separation technology, and has the characteristics of good technical compatibility, easy operability, low energy consumption, easy replacement of membrane components and the like, so that the electrodialysis is widely applied to seawater desalination, wastewater resource utilization and chemical production.
The performance of the traditional ion exchange membrane is greatly improved and can basically meet the industrial requirement, but in the application field of the ion exchange membrane, more solutions containing various ions are involved. In many electrodialysis applications, it is often desirable to selectively separate specific ions from a mixture using membranes. Techniques for separating specific cations from a mixture using electrodialysis are important in the fields of wastewater treatment, hydrometallurgy, and the like. Different from the ion exchange resin method and the liquid phase ion exchanger extraction method, the electrodialysis technology using the ion exchange membrane can continuously operate without adding acid, alkali and organic solvent in the process. Although the conventional ion exchange membrane can achieve separation between cations and anions, it cannot effectively achieve separation between homogeneous ions. With the development of electrodialysis technology and increasing industrial requirements, and due to the poor selective separation capability of traditional cation exchange membranes for specific cations, conventional electrodialysis, which has a low mono/multivalent separation efficiency, has been slightly debilitating.
Selective electrodialysis with monovalent separation capability has great potential in many fields, such as lithium extraction from salt lakes, brine purification, waste acid and waste alkali recovery, etc. As the core of selective electrodialysis, the preparation of high performance monovalent selective ion exchange membranes appears to be of paramount importance. Therefore, a great deal of research work has been successively conducted on the preparation of monovalent selective ion exchange membranes and the selective separation of specific ions by electrodialysis.
Since 1972, japan realized the production of common salt by directly concentrating seawater by electrodialysis. In order to directly produce relatively pure sodium chloride from seawater, cation exchange membranes are required to have preferential permselectivity for monovalent sodium ions. The development of monovalent ion selective separation membranes has therefore been promoted. The permeability of monovalent cations can be made significantly higher than that of high valence cations by increasing the crosslink density of the cation exchange membrane or by forming a very thin resin of high crosslink density on the surface of a cation exchange membrane of low crosslink density. The monovalent ion selectivity of the membrane can also be increased by introducing a small amount of anion exchange groups into the cation exchange membrane or forming a thin layer of positively charged polyelectrolyte on the surface of the cation exchange membrane.
Based on different separation mechanisms, the monovalent selective cation exchange membrane is prepared by the following method:
(1) The density of the film matrix is increased. In view of the difference in hydrated ionic radii between cations, attempts were initially made to achieve inter-ionic sieving by increasing the degree of crosslinking to produce a dense membrane matrix. For example, a monovalent selective cation exchange membrane can be prepared by performing polycondensation reaction on three monomers, namely phenol, sodium phenolsulfonate and formaldehyde, and the density of a membrane matrix is changed by changing the dosage of a cross-linking agent phenol; the permeability of calcium ions to sodium ions is greatly reduced with the increase of the phenol content. However, for polymeric cation exchange membranes prepared by sulfonation of copolymers of styrene and divinylbenzene, the permselectivity of calcium ions to sodium ions decreases only slightly with increasing amounts of crosslinker (divinylbenzene); this is because the decreasing ratio of the mobilities of calcium and sodium ions in the membrane phase with increasing divinylbenzene content is offset by the increasing inter-ion equilibrium constant. In the condensation type ion exchange membrane, the ion exchange equilibrium constant of calcium ions and sodium ions and the mobility ratio of the calcium ions to the sodium ions are reduced along with the increase of the phenol content. Therefore, in the ion exchange membrane having a high degree of crosslinking, it is necessary to keep the ion exchange equilibrium constants of calcium ions and sodium ions constant or low.
(2) The density of the film surface is increased. The interesting properties of conductive polymers such as polyacetylene, polypyrrole, polyaniline, polythiophene and the like are widely researched and applied. The conductive polymer is used as a material for improving the compactness of the surface of the membrane for preparing a monovalent selective cation exchange membrane. The polypyrrole has good affinity with a cation exchange membrane, and can be easily polymerized on the surface of the membrane to form a compact and rigid polypyrrole thin layer under the action of a proper oxidant. Aniline is also easy to polymerize and generate conductive polymers, and a cation exchange group of the membrane can perform ion exchange with protonated aniline to repel persulfate ions, so that a thin polyaniline layer can be generated on the surface of the membrane by immersing the cation exchange membrane subjected to aniline exchange into a solution containing persulfate ions. Experimental results show that this is an effective way to increase membrane selectivity relative to cations with widely differing ionic radii. While for cations with little difference in ionic radius, the improvement in membrane selectivity is insignificant.
(3) Forming a thin positively charged layer on the surface of the cation exchange membrane. The use of such cation exchange membranes is one of the key technologies for producing sodium chloride by electrodialysis concentration of seawater. The cation exchange membrane is immersed into the cation polyelectrolyte aqueous solution, and a layer of polyelectrolyte is adsorbed on the surface of the membrane through the ion exchange of sulfonic acid groups and the cation polyelectrolyte. However, in long-term electrodialysis industrial applications, the permselectivity of the membrane is gradually reduced due to the detachment of the polyelectrolyte layer. In response to the defects, it is reported that a monovalent selective cation exchange membrane is prepared by depositing chitosan quaternary ammonium salt with positive charge on the surface of the membrane by an electrodeposition method, and further performing a crosslinking treatment on the surface of the membrane. The results show that the modified membrane after crosslinking can maintain the selective separation performance of single/multiple-valence ions for a long time, and the service life of the membrane is prolonged. In addition, it has been reported that, based on this work, azide-functionalized chitosan is used for surface modification, and a modified layer is covalently bonded to a base film under an ultraviolet light condition, thereby increasing the durability of the film. It has also been reported that attempts have been made to sulfonyl chlorinate the sulfonic acid groups of cation exchange membranes with thionyl chloride, followed by reaction with dimethyldivinyldiamine and sulfonyl chloride groups and quaternization, so that a positively charged layer is formed on the membrane surface.
(4) The type of cation exchange groups in the membrane varies to affect the permselectivity of the cation. The interaction between cation exchange groups and cations in the membrane can change with different groups, and further the mobility ratio between cations and the ion exchange equilibrium constant are changed. It is reported that cation exchange membranes formed by condensation of salicylic acid, phenols and aldehydes acting as chelating agents exhibit this effect. It has also been reported that cation exchange membranes having chelate-forming groups such as sulfaquinoline and carboxylic acid have a higher selectivity for copper ions than for iron ions in diffusion dialysis. Meanwhile, a great deal of research has been conducted on cation exchange resins and cation exchange membranes having phosphoric acid groups. It is reported that the transport number of polyvalent cations to sodium ions in the membrane is relatively low compared to cation exchange membranes having sulfonic acid groups. In addition, there are patents reporting that the transference number of polyvalent cations to sodium ions is very low in a cation exchange membrane having both a phosphoric group and a nitro group.
Disclosure of Invention
The invention aims to provide a cation exchange membrane which has long service life and high selectivity on different ions and single/multivalent isotropic ions. The preparation method of the monovalent selective cation exchange membrane comprises the following steps:
(1) Taking a cation exchange membrane as a base membrane, soaking the base membrane in an oxidant aqueous solution, taking out the base membrane after soaking is finished, and removing liquid on the surface of the base membrane;
(2) Soaking the membrane obtained in the step (1) in an ethanol solution of pyrrole-2-carboxylic acid to polymerize the pyrrole-2-carboxylic acid in the membrane and on the surface of the membrane;
(3) Carrying out acid washing and then water washing on the membrane obtained in the step (2), and carrying out heating treatment after water washing;
(4) Soaking the membrane obtained in the step (3) in a mixed solution containing p-chloromethyl styrene and 2-sulfoethyl methacrylate for a short time, taking out the membrane, clamping the membrane between two inert sheet bodies, and then carrying out thermal polymerization treatment, wherein the two inert sheet bodies are removed after the thermal polymerization treatment;
(5) And (4) soaking the membrane obtained in the step (4) in an N, N-dimethylethanolamine aqueous solution, and then washing with water after soaking to obtain the monovalent selective cation exchange membrane.
In the step (1), the oxidant is ferric chloride, persulfate or hydrogen peroxide; the mass concentration of the oxidant aqueous solution is 1-10%; the soaking time of the basement membrane in the oxidant is 1-24h.
In the step (2), the concentration of the ethanol solution of pyrrole-2-carboxylic acid is 0.1-1mol/L, and the polymerization time is 1-24h.
In the step (3), the acid used for acid cleaning is hydrochloric acid or sulfuric acid with the concentration of 1-10%; the temperature of the heating treatment is 100-140 ℃; the heating treatment time is 12-24h.
In the step (4), the mixed solution is a liquid substance obtained by uniformly mixing p-chloromethyl styrene, 2-sulfoethyl methacrylate, divinylbenzene, azobisisobutyronitrile and N-methylpyrrolidone; the mol ratio of p-chloromethyl styrene to 2-sulfoethyl methacrylate is 1; the molar ratio of the divinylbenzene to the total amount of the p-chloromethyl styrene and the 2-sulfoethyl methacrylate is 1; the molar ratio of the azodiisobutyronitrile to the total amount of the p-chloromethyl styrene, the 2-sulfoethyl methacrylate and the divinylbenzene is 0.5 to 1.5; the mass ratio of the N-methylpyrrolidone to the total amount of the p-chloromethylstyrene, the 2-sulfoethyl methacrylate and the divinylbenzene is 20-40; the membrane is soaked in the mixed liquid for 10-60s; the thermal polymerization treatment temperature is 80-110 deg.C, and the time is 12-24h.
In the step (5), the concentration of the N, N-dimethylethanolamine aqueous solution is 1-10%; the soaking time of the membrane is 1-24h.
The cation exchange membrane as the base membrane of the present invention is a commercially available product, and for example, a homogeneous cation exchange membrane manufactured by Shandong Tianwei Membrane technology Co., ltd., japan, etc. can be selected; the inert sheet member in the present invention means a sheet member which does not chemically react with the film sheet in the thermal polymerization process, and for example, a glass sheet, a polyethylene terephthalate sheet, or the like can be used.
Compared with the prior art, the invention has the following beneficial effects:
(1) The compactness of the cation exchange membrane is effectively increased due to the formation of the pyrrole-2-carboxylic acid polymer, the conductivity of the membrane is improved due to the introduction of carboxylic acid groups and sulfonic acid groups, and the surface resistance of the membrane is not obviously improved due to the increase of the compactness of the membrane;
(2) P-chloromethyl styrene is polymerized on the surface of the membrane, N, N-dimethylethanolamine reacts with chloromethyl to generate quaternary ammonium groups, and a positively charged thin layer is formed on the surface of the membrane, so that the thin layer effectively improves the unit price selectivity of the membrane, is not easy to fall off, and has long service life;
(3) The positively charged thin layer may reduce the anion/cation selectivity of the cation exchange membrane, i.e., make the cation exchange membrane less selective for sodium ions in a sodium chloride solution, because the positive charge of the positively charged thin layer partially offsets the negative charge of the cation exchange membrane; the pyrrole-2-carboxylic acid and the 2-sulfoethyl methacrylate both have negative charges, so that the influence of the positive charges of the positively charged thin layer is counteracted, and the anion/cation selectivity of the prepared membrane is not reduced;
(4) The monovalent selective cation exchange membrane prepared by the method has the functions of pore size screening and electrostatic repulsion, and can effectively separate single/multivalent ions.
Detailed Description
The technical solutions of the present invention are further illustrated by the following examples, which are only used to show the technical concepts of the present invention and the feasibility thereof in detail, but not to limit the protection scope of the present invention, and the equivalents and modifications made by the technical concepts of the present invention are still within the protection scope of the present invention.
The following experimental procedure was used to produce small amounts of samples in the laboratory for resistance and selective permeability testing for research improvement and scale-up for continuous production.
Two important parameters characterizing the performance of Ion exchange membranes, membrane resistance and transport number, can be measured by means of a membrane potential test apparatus, the area resistance and transport number test using a test apparatus similar to that shown in FIG. 3.17 of Ion-exchange membrane separation processes (ISBN: 978-0-444-50236-0) by Heiner Strathmann. The two ends of the testing device are provided with metal electrodes, an ion exchange membrane is arranged in the middle of the testing device, ag/AgCl reference electrodes are arranged at the positions, close to the membrane, of the two sides of the membrane, and the effective membrane area S of the ion exchange membrane is 7cm 2 。
When testing the surface resistance, 0.5mol/L NaCl solution is injected into the device, 50mA direct current I is applied through the metal electrode, and the potential difference E of the two reference electrodes when the membrane sample is not placed is measured 2 And the potential difference E of the two reference electrodes when the membrane sample is placed 1 . The formula for calculating the sheet resistance R is as follows:
when the migration number is measured, the solutions on the two sides of the membrane sample are respectively 0.1mol/L NaCl solution and 0.5mol/L NaCl solution, no current is applied, and the potential difference E of the two reference electrodes is measured 1 The calculation formula of the membrane migration number t is as follows: the calculation formula of the membrane migration number t is as follows:
wherein E 2 For standard potential differences, R is the gas constant (8.314J/K/mol), T is the absolute temperature of the solution, F is the Faraday constant (96480C/mol), a 1 /a 2 Refers to the ratio of the activity of the solution on both sides of the membrane.
Test methods for characterizing monovalent selectivity of monovalent selective cation exchange membranes reference the English journal Separation and Purification Technology 2004, volume 40, pages 231-236. The testing device comprises two compartments made of organic glass, each compartment is provided with a stirring paddle, a calomel electrode is used for connecting two parts for measuring potential values, a membrane is clamped in a silica gel gasket between the two compartments, and the effective area of the membrane is 5.07cm 2 。
The membrane was soaked in 1mol/L of divalent ion electrolyte solution for two days before testing, and 100ml of 0.01mol/L of divalent ion electrolyte solution was added to both compartments and stirred, with the stirring speed controlled at 800-1000rpm. 1mol/L of monovalent ion electrolyte solution is added into the left compartment in batches and quantitatively, and the same volume of water is added into the right compartment to keep the concentration of divalent ion solution on both sides consistent. After stirring for a while, the potential values are read out, a series of potential concentration ratio values can be obtained, and the constant temperature is kept in the experimental process.
The technical solutions of the present invention are further illustrated by the following examples, which are only used to show the technical concepts of the present invention and the feasibility thereof in detail, but not to limit the protection scope of the present invention, and the equivalents and modifications made by the technical concepts of the present invention are still within the protection scope of the present invention.
The following experimental procedure can be used to produce small amounts of sample in the laboratory for resistance and permselectivity testing for research improvement and scale-up for continuous production.
Example 1
The preparation method of the monovalent selective cation exchange membrane comprises the following steps:
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the cation exchange membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the base membrane, and adsorbing and removing the ferric trichloride solution on the surface of the base membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 10g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours to polymerize the pyrrole-2-carboxylic acid in the interior and on the surface of the membrane; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 4.141g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dropwise adding 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 2.969g of divinylbenzene, putting the divinylbenzene into another beaker, adding 0.02g of azobisisobutyronitrile, carrying out magnetic stirring until the divinylbenzene is completely dissolved, mixing the liquid in the two beakers, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed liquid, and carrying out magnetic stirring until the p-chloromethyl styrene is uniformly mixed to obtain a mixed liquid;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the membrane, clamping the membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle, and placing the membrane in an oven at 80 ℃ for thermal polymerization for 12h; after the thermal polymerization treatment, cooling the membrane to room temperature and peeling two polyethylene terephthalate sheets;
(6) And (3) soaking the membrane obtained in the step (5) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared by the implementation is soaked in 0.5mol/L NaCl solution for more than 1 hour, and the measured membrane surface resistance and transference number data are as follows:
| film sample | Resistance (omega cm) 2 ） | Transference number |
| Example 1 | 6.88 | 0.985 |
；
Determination of the selectivity for mono-/polyvalent cations in sodium sulfate and magnesium sulfate solution, as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 1 | 1.1223 |
Example 2
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the cation exchange membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the base membrane, and adsorbing by using filter paper to remove the ferric trichloride solution on the surface of the base membrane;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 10g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours to polymerize the pyrrole-2-carboxylic acid in the interior and on the surface of the membrane; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 3.646g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dripping 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 1.732g of divinylbenzene, putting the divinylbenzene into another beaker, adding 0.018g of azobisisobutyronitrile, magnetically stirring until the divinylbenzene is completely dissolved, mixing the liquids in the two beakers together, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed liquid, and magnetically stirring until the p-chloromethyl styrene is uniformly mixed to obtain a mixed liquid;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the polypyrrole-2-carboxylic acid modified membrane, clamping the polypyrrole-2-carboxylic acid modified membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle of the polypyrrole-2-carboxylic acid modified membrane, and placing the polypyrrole-2-carboxylic acid modified membrane in an oven at 80 ℃ for thermal polymerization for 12h; cooling the membrane to room temperature after the thermal polymerization treatment and peeling two polyethylene terephthalate sheets;
(6) And (4) soaking the membrane obtained in the step (5) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are shown in the following table:
| film sample | Resistance (omega cm) 2 ） | Transference number |
| Example 2 | 5.97 | 0.981 |
；
Determination of the Mono/multivalent cation Selectivity in sodium sulfate and magnesium sulfate solution, as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 2 | 1.1155 |
Example 3
The preparation method of the monovalent selective cation exchange membrane comprises the following steps:
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the cation exchange membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the base membrane, and adsorbing and removing the ferric trichloride solution on the surface of the base membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 10g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours to polymerize the pyrrole-2-carboxylic acid in the interior and on the surface of the membrane; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 3.106g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dropwise adding 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 2.969g of divinylbenzene, putting the divinylbenzene into another beaker, adding 0.02g of azobisisobutyronitrile, carrying out magnetic stirring until the divinylbenzene is completely dissolved, mixing the liquid in the two beakers, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed liquid, and carrying out magnetic stirring until the p-chloromethyl styrene is uniformly mixed to obtain a mixed liquid;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the polypyrrole-2-carboxylic acid modified membrane, clamping the polypyrrole-2-carboxylic acid modified membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle of the polypyrrole-2-carboxylic acid modified membrane, and placing the polypyrrole-2-carboxylic acid modified membrane in an oven at 80 ℃ for thermal polymerization for 12h; after the thermal polymerization treatment, cooling the membrane to room temperature and peeling two polyethylene terephthalate sheets;
(6) And (3) soaking the membrane obtained in the step (5) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared in the example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transference number data are as follows:
| film sample | Resistance (omega cm) 2 ） | Transference number |
| Example 3 | 7.12 | 0.985 |
；
Determination of the selectivity for mono-/polyvalent cations in sodium sulfate and magnesium sulfate solution, as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 3 | 1.1201 |
Example 4
The preparation method of the monovalent selective cation exchange membrane comprises the following steps:
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the cation exchange membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the base membrane, and adsorbing and removing the ferric trichloride solution on the surface of the base membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 20g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours to polymerize the pyrrole-2-carboxylic acid in the interior and on the surface of the membrane; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 4.141g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dripping 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 2.969g of divinylbenzene, putting the divinylbenzene into another beaker, adding 0.02g of azobisisobutyronitrile, carrying out magnetic stirring until the divinylbenzene is completely dissolved, mixing the liquid in the two beakers, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed liquid, and carrying out magnetic stirring until the p-chloromethyl styrene is uniformly mixed to obtain a mixed liquid;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the polypyrrole-2-carboxylic acid modified membrane, clamping the polypyrrole-2-carboxylic acid modified membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle of the polypyrrole-2-carboxylic acid modified membrane, and placing the polypyrrole-2-carboxylic acid modified membrane in an oven at 80 ℃ for thermal polymerization for 12h; cooling the membrane to room temperature after the thermal polymerization treatment and peeling two polyethylene terephthalate sheets;
(6) And (4) soaking the membrane obtained in the step (5) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are shown in the following table:
| film sample | Resistance (omega cm) 2 ） | Number of migration |
| Example 4 | 6.23 | 0.982 |
；
Determination of the selectivity for mono-/polyvalent cations in sodium sulfate and magnesium sulfate solution, as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 4 | 1.1161 |
Example 5
The preparation method of the monovalent selective cation exchange membrane comprises the following steps:
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the cation exchange membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the membrane, and adsorbing and removing redundant ferric trichloride solution on the surface of the membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing in a beaker, adding 10g of ethanol, magnetically stirring until the mixture is completely dissolved, and soaking the membrane obtained in the step (1) in the solution for 2 hours; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 4.141g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dropwise adding 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 2.969g of divinylbenzene, placing the divinylbenzene into another beaker, adding 0.02g of azobisisobutyronitrile, carrying out magnetic stirring until the divinylbenzene is completely dissolved, mixing the liquid in the two beakers together, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed liquid, and carrying out magnetic stirring until the p-chloromethyl styrene is uniformly dissolved to obtain a mixed liquid;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the polypyrrole-2-carboxylic acid modified membrane, clamping the polypyrrole-2-carboxylic acid modified membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle of the polypyrrole-2-carboxylic acid modified membrane, and placing the polypyrrole-2-carboxylic acid modified membrane in an oven at 80 ℃ for thermal polymerization for 12h; after the thermal polymerization treatment, cooling the membrane to room temperature and peeling two polyethylene terephthalate sheets;
(6) And (4) soaking the membrane obtained in the step (5) in a 5% N, N-dimethylethanolamine aqueous solution for 10h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are shown in the following table:
| film sample | Resistance (omega cm) 2 ） | Number of migration |
| Example 5 | 13.22 | 0.983 |
；
Determination of the selectivity for mono/polyvalent cations in a solution of sodium chloride and magnesium sulfate, expressed as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 5 | 1.1211 |
；
The time for soaking the example 5 in the aqueous solution of N, N-dimethylethanolamine is prolonged, and the resistance of the example 5 is remarkably increased in comparison with the example 1 under the condition that the monovalent selectivity is consistent.
Comparative example 6
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, taking a cation exchange membrane as a base membrane, completely soaking the base membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the membrane, and adsorbing and removing the redundant ferric trichloride solution on the surface of the membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 10g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours; taking out after soaking;
(3) Soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain a polypyrrole-2-carboxylic acid modified membrane;
(4) Weighing 1.893g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, adding 0.01g of azobisisobutyronitrile, stirring and dissolving completely by magnetic force, weighing 3.249g of p-chloromethyl styrene and 1.484g of divinylbenzene, adding the p-chloromethyl styrene and the divinylbenzene in the beaker, and stirring uniformly by magnetic force to obtain a mixed solution;
(5) Soaking the polypyrrole-2-carboxylic acid modified membrane obtained in the step (3) in the mixed solution for 20s, taking out the polypyrrole-2-carboxylic acid modified membrane, clamping the polypyrrole-2-carboxylic acid modified membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle of the polypyrrole-2-carboxylic acid modified membrane, and placing the polypyrrole-2-carboxylic acid modified membrane in an oven at 80 ℃ for thermal polymerization for 12h; after the thermal polymerization treatment, cooling the membrane to room temperature and peeling two polyethylene terephthalate sheets;
(6) And (4) soaking the membrane obtained in the step (3) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the monovalent selective cation exchange membrane.
The membrane sample of the monovalent selective cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are shown in the following table:
| film sample | Resistance (omega cm) 2 ） | Number of migration |
| Example 6 | 6.69 | 0.972 |
；
Determination of the selectivity for mono/polyvalent cations in a solution of sodium chloride and magnesium sulfate, expressed as T Mg Na The results are shown in the following table:
| film sample | T Mg Na |
| Example 6 | 1.0305 |
；
As a comparative example, in example 6, in which 2-sulfoethyl methacrylate was not used, it is clear from the test data that both the different ion selectivity and the isotropic ion selectivity are significantly reduced.
Comparative example 7
(1) Weighing 5.4g of ferric trichloride hexahydrate, placing the ferric trichloride hexahydrate in a beaker, adding 107.7g of water, magnetically stirring until the ferric trichloride hexahydrate is completely dissolved, completely soaking the cation exchange membrane base membrane in the ferric trichloride aqueous solution, standing the base membrane at room temperature for 2 hours, taking out the membrane, and adsorbing the redundant ferric trichloride solution on the surface of the membrane by using filter paper;
(2) Weighing 0.6g of pyrrole-2-carboxylic acid, placing the pyrrole-2-carboxylic acid in a beaker, adding 10g of ethanol, magnetically stirring until the pyrrole-2-carboxylic acid is completely dissolved, and soaking the membrane obtained in the step (1) for 2 hours; taking out after soaking;
(3) And (3) soaking the membrane obtained in the step (2) in 5% dilute hydrochloric acid for washing, then washing with deionized water, heating the membrane at 130 ℃ for 12 hours after washing, and cooling the membrane to room temperature after heating treatment to obtain the cation exchange membrane.
The membrane sample of the cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are shown in the following table:
| film sample | Resistance (omega cm) 2 ） | Transference number |
| Example 7 | 10.96 | 0.975 |
As a comparative example, in example 7, only the cation-based membrane was modified with pyrrole-2 carboxylic acid, but the membrane achieved only an improvement in denseness, and since the resistance was high and the selectivity between different ions was low, it was not practical, and a unit price selectivity test was not performed.
Comparative example 8
(1) Weighing 4.141g of N-methylpyrrolidone, placing the N-methylpyrrolidone in a beaker, slowly dropwise adding 4.134g of 2-sulfoethyl methacrylate under magnetic stirring, and stirring until the N-methylpyrrolidone is completely dissolved; weighing 2.969g of divinylbenzene, putting the divinylbenzene into another beaker, adding 0.02g of azobisisobutyronitrile, carrying out magnetic stirring until the divinylbenzene is completely dissolved, mixing the liquid in the two beakers together, weighing 3.249g of p-chloromethyl styrene, adding the p-chloromethyl styrene into the mixed solution, and carrying out magnetic stirring until the p-chloromethyl styrene is uniformly mixed to obtain the mixed solution;
(2) Soaking a cation exchange membrane serving as a base membrane in the mixed solution for 20s, taking out the cation exchange membrane, clamping the cation exchange membrane between two polyethylene terephthalate sheets, squeezing out bubbles in the middle, and placing the polyethylene terephthalate sheets in an oven for thermal polymerization at 80 ℃ for 12h; after the thermal polymerization treatment, cooling the membrane to room temperature and peeling two polyethylene terephthalate sheets;
(3) And (3) soaking the membrane obtained in the step (2) in a 5% N, N-dimethylethanolamine aqueous solution for 5h, taking out, and washing with deionized water to obtain the cation exchange membrane.
The membrane sample of the cation exchange membrane prepared in this example was immersed in 0.5mol/L NaCl solution for 1 hour or more, and the measured membrane surface resistance and transport number data are as follows:
| film sample | Resistance (omega cm) 2 ） | Transference number |
| Example 8 | 4.40 | 0.964 |
；
As a comparative example, in example 8, since pyrrole-2-carboxylic acid modification was not performed and the denseness of the membrane was not improved, the selectivity between different ions was significantly reduced although the electrical resistance was low, and it was not practical and a unit price selectivity test was not performed.
The cation exchange membrane used as the base membrane in the above examples is produced by Shandong Tianwei Membrane technology, inc., and the product produced by Shandong Tianwei Membrane technology, inc. is only used to illustrate the feasibility of the present invention, but is not a limitation to the present invention.
Claims (3)
1. A preparation method of a monovalent selective cation exchange membrane is characterized by comprising the following steps:
(1) Taking a cation exchange membrane as a base membrane, soaking the base membrane in an oxidant aqueous solution, taking out the base membrane after soaking is finished, and removing liquid on the surface of the base membrane;
(2) Soaking the membrane obtained in the step (1) in an ethanol solution of pyrrole-2-carboxylic acid to polymerize the pyrrole-2-carboxylic acid in the membrane and on the surface of the membrane;
(3) Carrying out acid washing and then water washing on the membrane obtained in the step (2), and carrying out heating treatment after water washing;
(4) Soaking the membrane obtained in the step (3) in a mixed solution containing p-chloromethyl styrene and 2-sulfoethyl methacrylate for 10-60s, taking out the membrane, clamping the membrane between two inert sheet bodies, carrying out thermal polymerization treatment, and removing the two inert sheet bodies after the thermal polymerization treatment;
(5) Soaking the membrane obtained in the step (4) in an N, N-dimethylethanolamine aqueous solution, and washing with water after the soaking is finished to obtain a monovalent selective cation exchange membrane;
in the step (1), the oxidant is ferric chloride, persulfate or hydrogen peroxide; the mass concentration of the oxidant aqueous solution is 1-10%; soaking the base film in an oxidant for 1-24h;
in the step (2), the concentration of the ethanol solution of pyrrole-2-carboxylic acid is 0.1-1mol/L, and the polymerization time is 1-24h;
in the step (4), the mixed solution is a liquid substance obtained by uniformly mixing p-chloromethyl styrene, 2-sulfoethyl methacrylate, divinylbenzene, azobisisobutyronitrile and N-methylpyrrolidone; the mol ratio of the p-chloromethyl styrene to the 2-sulfoethyl methacrylate is 1; the molar ratio of the divinylbenzene to the total amount of the p-chloromethyl styrene and the 2-sulfoethyl methacrylate is 1; the molar ratio of azodiisobutyronitrile to the total amount of p-chloromethylstyrene, 2-sulfoethyl methacrylate and divinylbenzene is 0.5-1.5; the mass ratio of the N-methyl pyrrolidone to the total amount of the p-chloromethyl styrene, the 2-sulfoethyl methacrylate and the divinylbenzene is 20-40; the temperature of the thermal polymerization treatment is 80-110 ℃, and the time is 12-24h.
2. A method of preparing a monovalent selective cation exchange membrane according to claim 1, characterized in that: in the step (3), the acid used for acid cleaning is hydrochloric acid or sulfuric acid with the concentration of 1-10%; the temperature of the heating treatment is 100-140 ℃; the heating treatment time is 12-24h.
3. A method of preparing a monovalent selective cation exchange membrane according to claim 1, characterized in that: in the step (5), the concentration of the N, N-dimethylethanolamine aqueous solution is 1-10%; the soaking time of the membrane is 1-24h.
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| CN109092081B (en) * | 2018-08-30 | 2020-09-01 | 浙江工业大学 | Quaternized polyaniline monovalent selective cation exchange membrane and preparation method thereof |
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Denomination of invention: A preparation method of monovalent selective cation exchange membrane Effective date of registration: 20231215 Granted publication date: 20230314 Pledgee: Weifang Bank Co.,Ltd. Weifang High tech Branch Pledgor: SHANDONG TIANWEI MEMBRANE TECHNOLOGY Co.,Ltd. Registration number: Y2023980072153 |