WO2024218027A1 - Hollow fiber membranes comprising a poly(aryl ether sulfone) and a water-soluble polymer additive - Google Patents
Hollow fiber membranes comprising a poly(aryl ether sulfone) and a water-soluble polymer additive Download PDFInfo
- Publication number
- WO2024218027A1 WO2024218027A1 PCT/EP2024/060121 EP2024060121W WO2024218027A1 WO 2024218027 A1 WO2024218027 A1 WO 2024218027A1 EP 2024060121 W EP2024060121 W EP 2024060121W WO 2024218027 A1 WO2024218027 A1 WO 2024218027A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- membrane
- hollow fiber
- ether sulfone
- arylene ether
- poly
- Prior art date
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- 239000012528 membrane Substances 0.000 title claims abstract description 253
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 123
- 239000000654 additive Substances 0.000 title claims abstract description 57
- 230000000996 additive effect Effects 0.000 title claims abstract description 54
- 229920003169 water-soluble polymer Polymers 0.000 title claims abstract description 46
- 229920000110 poly(aryl ether sulfone) Polymers 0.000 title abstract description 9
- -1 poly(arylene ether sulfone Chemical class 0.000 claims description 160
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 129
- 229920000642 polymer Polymers 0.000 claims description 109
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 97
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 97
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 97
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 54
- 239000000446 fuel Substances 0.000 claims description 40
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 39
- 239000002344 surface layer Substances 0.000 claims description 39
- 239000002904 solvent Substances 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 30
- 210000004027 cell Anatomy 0.000 claims description 24
- 210000000170 cell membrane Anatomy 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 16
- 239000003586 protic polar solvent Substances 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- 238000000926 separation method Methods 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 9
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 9
- 230000035699 permeability Effects 0.000 claims description 8
- 230000004907 flux Effects 0.000 claims description 6
- 239000008246 gaseous mixture Substances 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 abstract description 17
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 108091006146 Channels Proteins 0.000 description 24
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 21
- 125000003118 aryl group Chemical group 0.000 description 17
- 229910006080 SO2X Inorganic materials 0.000 description 15
- 239000007788 liquid Substances 0.000 description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 13
- 125000000217 alkyl group Chemical group 0.000 description 13
- 239000000126 substance Substances 0.000 description 13
- 150000001768 cations Chemical class 0.000 description 12
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 11
- 239000007789 gas Substances 0.000 description 11
- 229920006393 polyether sulfone Polymers 0.000 description 10
- 229920012287 polyphenylene sulfone Polymers 0.000 description 9
- 125000001140 1,4-phenylene group Chemical group [H]C1=C([H])C([*:2])=C([H])C([H])=C1[*:1] 0.000 description 8
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 8
- 150000001298 alcohols Chemical class 0.000 description 8
- 125000000732 arylene group Chemical group 0.000 description 8
- 229920002492 poly(sulfone) Polymers 0.000 description 8
- 238000005345 coagulation Methods 0.000 description 7
- 230000015271 coagulation Effects 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000000460 chlorine Substances 0.000 description 6
- 229910052801 chlorine Inorganic materials 0.000 description 6
- 150000002367 halogens Chemical class 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 6
- 229910052701 rubidium Inorganic materials 0.000 description 6
- 125000000542 sulfonic acid group Chemical group 0.000 description 6
- UBKQRASXZMLQRJ-UHFFFAOYSA-N 2-phenylsulfanylethanamine Chemical compound NCCSC1=CC=CC=C1 UBKQRASXZMLQRJ-UHFFFAOYSA-N 0.000 description 5
- 239000004695 Polyether sulfone Substances 0.000 description 5
- 125000003545 alkoxy group Chemical group 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 125000004957 naphthylene group Chemical group 0.000 description 5
- 238000001637 plasma atomic emission spectroscopy Methods 0.000 description 5
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 4
- 229920003082 Povidone K 90 Polymers 0.000 description 4
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 125000000753 cycloalkyl group Chemical group 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- YNPNZTXNASCQKK-UHFFFAOYSA-N phenanthrene Chemical compound C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 description 4
- 229920000233 poly(alkylene oxides) Polymers 0.000 description 4
- 229920001451 polypropylene glycol Polymers 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 238000004566 IR spectroscopy Methods 0.000 description 3
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000000429 assembly Methods 0.000 description 3
- 230000000712 assembly Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000005227 gel permeation chromatography Methods 0.000 description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 3
- 239000005518 polymer electrolyte Substances 0.000 description 3
- 229910000027 potassium carbonate Inorganic materials 0.000 description 3
- 238000009987 spinning Methods 0.000 description 3
- VDZOOKBUILJEDG-UHFFFAOYSA-M tetrabutylammonium hydroxide Chemical compound [OH-].CCCC[N+](CCCC)(CCCC)CCCC VDZOOKBUILJEDG-UHFFFAOYSA-M 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 125000001989 1,3-phenylene group Chemical group [H]C1=C([H])C([*:1])=C([H])C([*:2])=C1[H] 0.000 description 2
- 238000005160 1H NMR spectroscopy Methods 0.000 description 2
- 125000004959 2,6-naphthylene group Chemical group [H]C1=C([H])C2=C([H])C([*:1])=C([H])C([H])=C2C([H])=C1[*:2] 0.000 description 2
- HIXDQWDOVZUNNA-UHFFFAOYSA-N 2-(3,4-dimethoxyphenyl)-5-hydroxy-7-methoxychromen-4-one Chemical compound C=1C(OC)=CC(O)=C(C(C=2)=O)C=1OC=2C1=CC=C(OC)C(OC)=C1 HIXDQWDOVZUNNA-UHFFFAOYSA-N 0.000 description 2
- YEBLAXBYYVCOLT-UHFFFAOYSA-N 2-hydroxy-n,n-dimethylpropanamide Chemical compound CC(O)C(=O)N(C)C YEBLAXBYYVCOLT-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000005708 Sodium hypochlorite Substances 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 150000001491 aromatic compounds Chemical class 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 125000001309 chloro group Chemical group Cl* 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- IPZJQDSFZGZEOY-UHFFFAOYSA-N dimethylmethylene Chemical group C[C]C IPZJQDSFZGZEOY-UHFFFAOYSA-N 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- GAEKPEKOJKCEMS-UHFFFAOYSA-N gamma-valerolactone Chemical compound CC1CCC(=O)O1 GAEKPEKOJKCEMS-UHFFFAOYSA-N 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- NXPPAOGUKPJVDI-UHFFFAOYSA-N naphthalene-1,2-diol Chemical compound C1=CC=CC2=C(O)C(O)=CC=C21 NXPPAOGUKPJVDI-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 239000002798 polar solvent Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 229920000412 polyarylene Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 229920005604 random copolymer Polymers 0.000 description 2
- 230000036647 reaction Effects 0.000 description 2
- 229930195734 saturated hydrocarbon Natural products 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
- 229960005076 sodium hypochlorite Drugs 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000002336 sorption--desorption measurement Methods 0.000 description 2
- 238000006277 sulfonation reaction Methods 0.000 description 2
- 150000003457 sulfones Chemical class 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- IFLREYGFSNHWGE-UHFFFAOYSA-N tetracene Chemical compound C1=CC=CC2=CC3=CC4=CC=CC=C4C=C3C=C21 IFLREYGFSNHWGE-UHFFFAOYSA-N 0.000 description 2
- WHIRALQRTSITMI-UJURSFKZSA-N (1s,5r)-6,8-dioxabicyclo[3.2.1]octan-4-one Chemical compound O1[C@@]2([H])OC[C@]1([H])CCC2=O WHIRALQRTSITMI-UJURSFKZSA-N 0.000 description 1
- ZFPGARUNNKGOBB-UHFFFAOYSA-N 1-Ethyl-2-pyrrolidinone Chemical compound CCN1CCCC1=O ZFPGARUNNKGOBB-UHFFFAOYSA-N 0.000 description 1
- BNXZHVUCNYMNOS-UHFFFAOYSA-N 1-butylpyrrolidin-2-one Chemical compound CCCCN1CCCC1=O BNXZHVUCNYMNOS-UHFFFAOYSA-N 0.000 description 1
- 125000005916 2-methylpentyl group Chemical group 0.000 description 1
- 125000005917 3-methylpentyl group Chemical group 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- BRDWIEOJOWJCLU-LTGWCKQJSA-N GS-441524 Chemical compound C=1C=C2C(N)=NC=NN2C=1[C@]1(C#N)O[C@H](CO)[C@@H](O)[C@H]1O BRDWIEOJOWJCLU-LTGWCKQJSA-N 0.000 description 1
- VSNHCAURESNICA-UHFFFAOYSA-N Hydroxyurea Chemical compound NC(=O)NO VSNHCAURESNICA-UHFFFAOYSA-N 0.000 description 1
- 108090000862 Ion Channels Proteins 0.000 description 1
- 102000004310 Ion Channels Human genes 0.000 description 1
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 229920003081 Povidone K 30 Polymers 0.000 description 1
- 229920003291 Ultrason® E Polymers 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000002479 acid--base titration Methods 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 150000005215 alkyl ethers Chemical group 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000000010 aprotic solvent Substances 0.000 description 1
- 150000001502 aryl halides Chemical class 0.000 description 1
- 125000004104 aryloxy group Chemical group 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- AGEZXYOZHKGVCM-UHFFFAOYSA-N benzyl bromide Chemical compound BrCC1=CC=CC=C1 AGEZXYOZHKGVCM-UHFFFAOYSA-N 0.000 description 1
- KCXMKQUNVWSEMD-UHFFFAOYSA-N benzyl chloride Chemical compound ClCC1=CC=CC=C1 KCXMKQUNVWSEMD-UHFFFAOYSA-N 0.000 description 1
- 229940073608 benzyl chloride Drugs 0.000 description 1
- 125000000051 benzyloxy group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])O* 0.000 description 1
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- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- UBAZGMLMVVQSCD-UHFFFAOYSA-N carbon dioxide;molecular oxygen Chemical compound O=O.O=C=O UBAZGMLMVVQSCD-UHFFFAOYSA-N 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
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- 238000001816 cooling Methods 0.000 description 1
- 125000001995 cyclobutyl group Chemical group [H]C1([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 125000004850 cyclobutylmethyl group Chemical group C1(CCC1)C* 0.000 description 1
- 125000000582 cycloheptyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000004210 cyclohexylmethyl group Chemical group [H]C([H])(*)C1([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C1([H])[H] 0.000 description 1
- 125000000640 cyclooctyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C([H])([H])C1([H])[H] 0.000 description 1
- 125000001511 cyclopentyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 125000001559 cyclopropyl group Chemical group [H]C1([H])C([H])([H])C1([H])* 0.000 description 1
- 125000004186 cyclopropylmethyl group Chemical group [H]C([H])(*)C1([H])C([H])([H])C1([H])[H] 0.000 description 1
- 125000002704 decyl group Chemical group [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])* 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
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- 125000003438 dodecyl group Chemical group [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])* 0.000 description 1
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- 125000003187 heptyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
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- 125000002510 isobutoxy group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])O* 0.000 description 1
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- WEFZXWJJPHGTTN-UHFFFAOYSA-N methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate Chemical compound COC(=O)C(C)CCC(=O)N(C)C WEFZXWJJPHGTTN-UHFFFAOYSA-N 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
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- QEDKUQXNXOLGMP-UHFFFAOYSA-N n,n-diethyl-2-hydroxypropanamide Chemical compound CCN(CC)C(=O)C(C)O QEDKUQXNXOLGMP-UHFFFAOYSA-N 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
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- VWBWQOUWDOULQN-UHFFFAOYSA-N nmp n-methylpyrrolidone Chemical compound CN1CCCC1=O.CN1CCCC1=O VWBWQOUWDOULQN-UHFFFAOYSA-N 0.000 description 1
- 125000001400 nonyl 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])[H] 0.000 description 1
- 125000002347 octyl 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])[H] 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
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- 125000000951 phenoxy group Chemical group [H]C1=C([H])C([H])=C(O*)C([H])=C1[H] 0.000 description 1
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- 229960001749 practolol Drugs 0.000 description 1
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- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
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- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 125000002914 sec-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 1
- 125000001273 sulfonato group Chemical class [O-]S(*)(=O)=O 0.000 description 1
- 150000003460 sulfonic acids Chemical class 0.000 description 1
- PGAPATLGJSQQBU-UHFFFAOYSA-M thallium(i) bromide Chemical compound [Tl]Br PGAPATLGJSQQBU-UHFFFAOYSA-M 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 125000002948 undecyl 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])[H] 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- 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
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/02—Hollow fibre modules
-
- 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
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0011—Casting solutions therefor
-
- 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
- B01D69/08—Hollow fibre membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/44—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26-B01D71/42
- B01D71/441—Polyvinylpyrrolidone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
- B01D71/68—Polysulfones; Polyethersulfones
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
- H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
- H01M8/04126—Humidifying
- H01M8/04149—Humidifying by diffusion, e.g. making use of membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2315/00—Details relating to the membrane module operation
- B01D2315/22—Membrane contactor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/02—Hydrophilization
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/12—Specific ratios of components used
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/15—Use of additives
- B01D2323/218—Additive materials
- B01D2323/2182—Organic additives
- B01D2323/21839—Polymeric additives
- B01D2323/2187—Polyvinylpyrolidone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/20—Specific permeability or cut-off range
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- Hollow fiber membranes comprising a poly(aryl ether sulfone) and a water-soluble polymer additive
- the present invention relates to a hollow fiber membrane made from blends of poly(aryl ether sulfone) and a water-soluble polymer additive, manufacturing methods therefor and their uses. Furthermore, the present invention relates to a separation element, membrane module, separation system, membrane cartridge and fuel cell membrane humidifier containing such membrane or membranes.
- PEM polymer electrolyte membrane
- FC carbon dioxide emission free transportation applications
- ambient air serves as source of oxygen necessary for the fuel cell reaction.
- gas-to-gas humidifiers are used to transfer water vapor from the cathode exhaust gases to the intake gas.
- the humidifier may contain a hollow fiber membrane and selectively provides water vapor to the fuel cell membrane.
- PFSA perfluorinated sulfonic acid polymers
- PESLI polyethersulfone
- PSU polysulfone
- LIS2021154624 A1 is directed to a composite hollow fiber membrane including a hollow fiber membrane and a pollutant entrapping layer coated on the inner surface of the hollow fiber membrane, wherein the membrane can be used in a membrane humidifier for a fuel cell. From environmental standpoints, halogen-containing polymeric membrane material is unfavorable.
- hydrophilic water-soluble polymers such as polyvinylpyrrolidone (PVP) are used as additives to adjust the viscosity of the polymer solution.
- PVP polyvinylpyrrolidone
- Such additives may also act as place holders for pores in the filtration layer of the hollow fiber membranes (e.g. S. Munari, Desalination 1988, 70, 265-275).
- the filtration layer is formed by removal of the hydrophilic polymer from the polyarylsulfone matrix. It can selectively be removed by chemical treatment with hypochlorite (I. M. Wienk et.al, Journal Polymer Science: Part A: Polymer Chemistry 1995, 33, 49-54).
- an object of the invention was finding a suitable membrane for fuel cell humidifiers that can selectively withhold gas and transmit water vapor to the fuel cell membrane.
- a further object was the provision of a selective and halogen-free free membrane with high water vapor transmission useful in fuel cell membrane humidifiers.
- a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), the membrane comprising at least one polymer (P) selected from a poly(arylene ether sulfone) and a sulfonated poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a fuel cell membrane humidifier and the use of such membrane for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
- P polymer
- A water-soluble polymer additive
- PVP polyvinylpyrrolidone
- the inventive hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), the membrane comprising at least one polymer (P) selected from a poly(arylene ether sulfone) and a sulfonated poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising at least 10 % by weight, based on the total weight of the membrane, polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80, exhibits high water transfer rates while selectively withholding undesired gas contained in the gaseous exhaust composition supplied to the fuel cell.
- the inventive membranes and assemblies containing the inventive membranes are particularly useful for humidifiers in polymer electrolyte membrane fuel cells.
- membrane means a semipermeable structure acting as a selective barrier, allowing some particles, substances or chemicals to pass through, while retaining others.
- membranes are applied in various liquid and gaseous separations.
- the membrane of the present invention is a hollow fiber membrane, wherein it may be a single bore hollow fiber or multiple bore hollow fiber membrane.
- a semipermeable barrier is in the form of a hollow fiber.
- the number of channels is typically 2 to 19.
- the multiple bore hollow fiber membrane comprises two or three channels.
- the multiple bore hollow fiber membrane comprises 5 to 9 channels.
- the multiple bore hollow fiber membrane comprises seven channels.
- the multiple bore hollow fiber membrane comprises 20 to 100 channels.
- the shape of the bore or bores may vary. Normally, the membranes according to the invention have an essentially circular, ellipsoid or rectangular diameter. Preferably, membranes according to the invention are essentially circular, i.e. the bores have an essentially circular diameter.
- such bores have an essentially ellipsoid diameter.
- channels have an essentially rectangular diameter. In some cases, the actual form of such channels may deviate from the idealized circular, ellipsoid or rectangular form.
- the hollow fiber membrane channels have an inner and an outer diameter. The difference of the outer diameter and the inner diameter is the thickness of the hollow fiber membrane.
- such channels have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 0.05 mm to 3 mm, preferably 0.5 to 2 mm, more preferably 0.9 to 1.5 mm.
- such channels have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) in the range from 0.2 to 0.9 mm.
- hollow fiber membranes according to the invention or used according to the invention have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 2 to 10 mm, preferably 3 to 8 mm, more preferably 4 to 6 mm.
- hollow fiber membranes according to the invention or used according to the invention have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 2 to 4 mm.
- the hollow fiber membrane can have any thickness.
- the thickness of the membrane is in the range from 20 to 150 pm, preferably in the range from 20 to 100 pm and most preferably in the range from 30 to 60 pm.
- multi-bore hollow fiber membranes contain channels with an essentially rectangular shape, these channels can be arranged in a row. If the channels in a multi-bore hollow fiber membrane have essentially circular shape, these channels are preferably arranged such that a central channel is surrounded by the other channels.
- a membrane comprises one central channel and for example four, six or 18 further channels arranged cyclically around the central channel.
- the wall thickness in such multiple channel membranes is normally from 0.02 to 1 mm at the thinnest position, preferably 30 to 500 pm, more preferably 100 to 300 pm.
- the inventive hollow fiber membrane and the hollow fiber membrane used according to the invention respectively, comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone).
- the poly(arylene ether sulfone) is non-sulfonated if it is not explicitly mentioned.
- Poly(arylene ether sulfone) polymers belong to the group of high temperature resistant polymers showing high heat resistance, excellent mechanical performance and inherent flame re- tardancy (E.M. Koch, H.-M. Walter, Kunststoffe 80 (1990) 1146; E. Ddring, Kunststoffe 80, (1990) 1149, N. Inchaurondo-Nehm, Kunststoffe 2008 190).
- Polyarylene(ether)sulfones are generally known to a person skilled in the art.
- Non-sulfonated within the context of the present invention means that the poly(arylene ether sulfone) polymer does not comprise any -SO2X group, wherein X is selected from the group consisting of Cl’ and O’ combined with one cation equivalent.
- One cation equivalent within the context of the present invention means one cation of a single positive charge or one charge equivalent of a cation with two or more positive charges, for example, H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NH 4 + .
- a sulfonated poly(arylene ether sulfone) or “a poly(arylene ether sulfone)”, respectively, in the present application is understood to mean exactly one sulfonated poly(arylene ether sulfone) polymer or poly(arylene ether sulfone) polymer, respectively, and also mixtures of two or more sulfonated poly(arylene ether sulfone) polymers or of two or more poly(arylene ether sulfone) polymers, respectively.
- the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention comprises a poly(arylene ether sulfone) polymer (P) as defined or preferably defined herein.
- the hollow fiber membrane does not contain any sulfonated poly(arylene ether sulfone).
- the hollow fiber membrane comprises preferably at least 50 % by weight of the poly(arylene ether sulfone) polymer (P), more preferably at least 60 % by weight and most preferably at least 70 % by weight of the poly(arylene ether sulfone) polymer (P) based on the total weight of the hollow fiber membrane.
- the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention comprises a sulfonated poly(arylene ether sulfone) polymer (P) as defined or preferably defined herein.
- the hollow fiber membrane does not contain any (non-sulfonated) poly(arylene ether sulfone).
- the hollow fiber membrane comprises preferably at least 50 % by weight of the sulfonated poly(arylene ether sulfone) polymer (P), more preferably at least 60 % by weight and most preferably at least 70 % by weight of the sulfonated poly(arylene ether sulfone) polymer (P) based on the total weight of the hollow fiber membrane.
- the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention comprises a sulfonated poly(arylene ether sulfone) as defined or preferably defined herein and a poly(arylene ether sulfone) as defined or preferably defined herein.
- the hollow fiber membrane preferably comprises from 5 to 90% by weight, more preferably from 7.5 to 80% by weight, of the sulfonated poly(arylene ether sulfone) polymer (P), based on the total weight of the membrane.
- the membrane also preferably comprises from 10 to 95% by weight, more preferably from 20 to 92.5% by weight, of the poly(arylene ether sulfone) polymer (P), based on the total weight of the membrane.
- the hollow fiber membrane comprises from 5 to 90% by weight of the sulfonated poly(arylene ether sulfone) polymer and from 10 to 95% by weight of the poly(arylene ether sulfone) polymer, based in each case on the total weight of the membrane.
- the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (I) wherein the definitions of the symbols t, q, Q, T, Y, Ar and Ar 1 are as follows: t, q independently of one another 0, 1 , 2 or 3;
- Ar and Ar 1 independently of one another (C6-Cis)arylene; and where at least one unit (I) comprises an arylene group which is substituted with at least one -SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NHY.
- Q, T or Y is a chemical bond, this is understood to mean that the adjacent group to the left and the adjacent group to the right are bonded directly to one another via a chemical bond.
- At least one of the groups consisting of Q, T and Y being -SO2- means that at least one group in formula (I) is -SO2-.
- t and q are independently 0 or 1.
- Q, T, and Y in formula II are independently selected from a chemical bond, -O-, -SO2- and -CR a R b -, with the proviso that at least one of Q, T, and Y is present and is -SO2-.
- R a and R b are, independently of one another, hydrogen or (Ci-C4)alkyl.
- R a and R b are preferably independently selected from hydrogen, (Ci-Ci2)alkyl, (C1- Ci2)alkoxy and (Ce-Cisjaryl.
- (Ci-Ci2)alkyl refers to linear or branched saturated hydrocarbon groups having from 1 to 12 carbon atoms.
- the following moieties are particularly encompassed: (Ci-Ce)alkyl, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, 2- or 3-methylpentyl, as well as (C?-Ci2)alkyl, e.g. unbranched heptyl, octyl, nonyl, decyl, undecyl, lauryl, and the singly branched or multibranched analogs thereof.
- Ci-Ci2-alkoxy refers to a linear or branched alkyl group having 1 to 12 carbon atoms which is bonded via an oxygen, at any position in the alkyl group, e.g. methoxy, ethoxy, n- propoxy, 1 -methylethoxy, butoxy, 1-methyhpropoxy, 2-methylpropoxy or 1 ,1 -dimethylethoxy.
- (C3-Ci2)cycloalkyl refers to monocyclic saturated hydrocarbon radicals having 3 to 12 carbon ring members and particularly comprises (Cs-Csjcycloalkyl, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylethyl, -propyl, -butyl, -pentyl, -hexyl, cyclohexylmethyl, -dimethyl, and -trimethyl.
- Cs-Csjcycloalkyl e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohepty
- Ar and Ar 1 are independently of one another a (C6-Cis)-arylene group. It may be preferred that, according to a specific embodiment, Ar 1 is an unsubstituted (Ce-Ci2)arylene group.
- Ar and Ar 1 are independently selected from phenylene, bisphenylene and naphthylene groups, and from arylene groups that derive from anthracene, from phenanthrene, or from naphthacene.
- Ar and Ar 1 are independently selected from 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4-phenylene, 1 ,6-naphthylene, 1 ,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.
- Ar and Ar 1 are independently selected from phenylene and naphthylene groups, such as independently selected from 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4- phenylene, 1 ,6-naphthylene, 1 ,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, more specifically independently selected from 1 ,4-phenylene, 1 ,3-phenylene and naphthylene.
- Ar and Ar 1 are independently selected from arylene groups that derive from anthracene, from phenanthrene, or from naphthacene.
- Ar and Ar 1 are independently selected from 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.
- Preferred sulfonated poly(arylene ether sulfone) polymers are those comprising at least one of the following units la to Io as repeat structural units, wherein at least one unit (I) comprises an arylene group which is substituted with at least one -SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NH 4 + :
- Particularly preferred units of the general formula (I) are the units la, Ig and Ik. It is also particularly preferred when the sulfonated poly(arylene ether sulfone) polymers are formed essentially from one kind of units of the general formula (I), especially from a unit selected from la, Ig and Ik.
- sulfonated poly(arylene ether sulfone) polymers (A) formed from the aforementioned repeat unit are referred to as sulfonated polyphenylene sulfone (PPSU) (formula Ig).
- PSU sulfonated polysulfone
- PPSLI sulfonated poly(arylene ether sulfone)
- PESLI sulfonated poly(ether sulfone)
- the sulfonated poly(arylene ether sulfone) polymer is a copolymer formed from poly(ether sulfone) (PESLI) units and poly(phenylene sulfone) (PPSLI) units, wherein at least one unit comprises an arylene group which is substituted with at least one - SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NH 4 + .
- This copolymer may, for example, be a random copolymer or a block copolymer.
- PESLI poly(ether sulfone)
- PPSLI poly(phenylene sulfone)
- the sulfonated poly(arylene ether sulfone) polymer is a copolymer formed from poly(ether sulfone) (PESLI) units and poly(phenylene sulfone) (PPSLI) units
- the sulfonated poly(arylene ether sulfone) polymer comprises in the range from 1 to 20 mol% of poly(phenylene sulfone) (PPSLI) units and from 80 to 99 mol% of poly(ether sulfone) (PESLI) units, in each case based on the total sum of all repeating units.
- the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (III)
- the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (V) It is also possible that the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (III) and/or formula (IV) and/or formula (V).
- the sulfonated poly(arylene ether sulfone) polymer preferably has a number-average molecular weight (MN) of from 10 000 to 35 000 g/mol, determined by gel permeation chromatography in dimethylacetamide as solvent versus narrowly distributed polymethyl methacrylate as standard.
- MN number-average molecular weight
- the sulfonated poly(arylene ether sulfone) polymer preferably has a content of free acid of less than 3 mg KOH/g sulfonated poly(arylene ether sulfone) polymer, determined by titration with 0.1 mol/l tetrabutylammoniumhydroxide solution (TBAH, in methanol/toluene) against a Solvotrode electrode (Metrohm).
- TBAH tetrabutylammoniumhydroxide solution
- the sulfonated poly(arylene ether sulfone) polymer can be prepared by any method known to the person skilled in the art.
- the sulfonated poly(arylene ether sulfone) polymer is produced by treating a respective non-sulfonated poly(arylene ether sulfone) polymer with at least one sulfonating agent.
- the at least one sulfonating agent is suitably any compound known to a person skilled in the art that is capable of introducing at least one SO2X group, where X is Cl or O', combined with one cation equivalent, where the cation equivalent is H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NH 4 + , into an aromatic ring of the non-sulfonated poly(arylene ether sulfone) polymer.
- the SO2X group is preferably a sulfonic acid group (-SO3H) or a group capable of reacting with water to form a sulfonic acid group.
- Groups of this type are known to a person skilled in the art and include, for example, chlorosulfonyl groups (-SO2CI).
- the SO2X group is more preferably therefore a sulfonic acid group (-SO3H) or a chlorosulfonyl group (-SO2CI), most preferably the SO2X group is a sulfonic acid group (-SO3H).
- the reaction of the non-sulfonated poly(arylene ether sulfone) polymer with the at least one sulfonating agent preferably sulfonates at least one of the aromatic rings of the non-sulfonated poly(arylene ether sulfone) polymer at least partially.
- the mechanism of the sulfonation reaction is known as such to a person skilled in the art. Thereby it is particularly preferable for the sulfonation reaction to replace a hydrogen atom of the aromatic ring by a sulfonic acid group (-SO3H).
- sulfonated poly(arylene ether sulfone) polymer typically has from 0.001 to 1 , preferably from 0.005 to 0.1 , and more preferably from 0.01 to 0.08 SO2X groups per aromatic ring.
- the number of SO2X groups per aromatic ring is determined by averaging over all the aromatic rings of the sulfonated poly(arylene ether sulfone) polymer.
- the number of SO2X groups in the sulfonated poly(arylene ether sulfone) polymer is divided by the number of aromatic rings in the sulfonated poly(arylene ether sulfone) polymer.
- Methods of determining the number of SO2X groups and the number of aromatic rings, each in the sulfonated poly(arylene ether sulfone) polymer, are known to a person skilled in the art.
- the number of SO2X groups is determinable, for example, by acid-base titration or by spectroscopic methods such as H 1 NMR spectroscopy or IR spectroscopy (infrared spectroscopy).
- Sulfonated aromatic polymers having SO2X groups on the aromatic ring display characteristic peaks and bands, making it possible to determine the number of SO2X groups per aromatic ring in the sulfonated poly(arylene ether sulfone) polymer.
- the ratio of sulfonated to non-sulfonated aromatic rings can also be determined by these methods, in particular by H 1 NMR spectroscopy.
- the (non-sulfonated) poly(arylene ether sulfone) polymer is composed of units of the general formula (I) wherein the definitions of the symbols t, q, Q, T, Y, Ar and Ar 1 are as follows: t, q independently of one another 0, 1 , 2 or 3;
- R a and R b independently of one another are a hydrogen atom, (Ci-Ci2)alkyl, (Ci-Ci2)alkoxy, (C3-Ci2)cycloalkyl or a (C6-Cis)aryl group, and wherein at least one of Q, T, and Y is present and is -SO2-; and
- Ar and Ar 1 independently of one another (C6-Cis)arylene.
- Q, T or Y is a chemical bond
- t and q are independently 0 or 1.
- Q, T, and Y in formula II are independently selected from a chemical bond, -O-, -SO2- and -CR a R b -, with the proviso that at least one of Q, T, and Y is present and is -SO2-.
- R a and R b are, independently of one another, hydrogen or (Ci-C4)alkyl.
- R a and R b are preferably independently selected from hydrogen, (Ci-Ci2)alkyl, (Ci- Ci2)alkoxy and (C6-Cis)aryl.
- Poly(arylene ether sulfone) polymers comprising at least one of the units la to Io as defined above as repeat structural units may be preferred.
- repeat units in addition to the units la to Io that may preferably be present, are those in which one or more 1 ,4-phenylene units deriving from hydroquinone have been replaced by 1 ,3-phenylene units deriving from resorcinol, or by naphthylene units deriving from dihydroxynaphthalene.
- Units of the general formula (I) that are particularly preferred are the units la, Ig, and/or Ik.
- the poly(arylene ether sulfone) polymer is in essence composed of one type of unit of the general formula (I), whereby said one type may particularly be selected from la, Ig, and Ik.
- the poly(arylene ether sulfone) polymer is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T is a chemical bond, and Y is SO2.
- This poly(arylene ether sulfone) is also termed polyphenylene sulfone (PPSU) (formula Ig).
- the poly(arylene ether sulfone) polymer is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T is C(CH3)2, and Y is SO2.
- This poly(arylene ether sulfone) is also termed polysulfone (PSU) (formula la).
- the poly(arylene ether sulfone) polymer (P) is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T and Y are SO2.
- This poly(arylene ether sulfone) is also termed polyether sulfone (PESU) (formula Ik).
- the weight-average molar masses M w of the poly(arylene ether sulfone) polymer (P) are preferably from 10 000 to 40 000 g/mol, more specifically from 10 000 to 37 000 g/mol, in particular from 12 000 to 35 000 g/mol, particularly preferably from 14 000 to 33 000 g/mol, determined by means of gel permeation chromatography in dimethylacetamide as solvent against narrowly distributed polymethyl methacrylate as standard.
- the synthesis of the poly(arylene ether sulfone) polymers can generally be done by polycondensation of appropriate monomers in dipolar-aprotic solvents at elevated temperatures (R.N. Johnson et.al., J. Polym. Sci. A-1 5 (1967) 2375, J.E. McGrath et.al., Polymer 25 (1984) 1827).
- the known poly(arylene ether sulfone) polymers usually have halogen end groups, in particular -F or -Cl, or phenolic OH end groups or phenolate end groups, where the latter can be present as such or in reacted form, in particular in the form of -OCH3 end groups.
- reaction in aprotic polar solvents and in the presence of anhydrous alkali metal carbonate, in particular sodium carbonate, potassium carbonate, calcium carbonate, or a mixture thereof, very particularly preferably potassium carbonate, between at least one aromatic compound having two halogen substituents and at least one aromatic compound having two functional groups reactive toward abovementioned halogen substituents.
- anhydrous alkali metal carbonate in particular sodium carbonate, potassium carbonate, calcium carbonate, or a mixture thereof, very particularly preferably potassium carbonate, between at least one aromatic compound having two halogen substituents and at least one aromatic compound having two functional groups reactive toward abovementioned halogen substituents.
- anhydrous alkali metal carbonate in particular sodium carbonate, potassium carbonate, calcium carbonate, or a mixture thereof, very particularly preferably potassium carbonate
- N-methyl-2-pyrrolidone as solvent and potassium carbonate as base.
- the poly(arylene ether sulfone) polymers have either halogen end groups, in particular chlorine end groups, or etherified end groups, in particular alkyl ether end groups, these being obtainable via reaction of the OH or, respectively, phenolate end groups with suitable etherifying agents.
- suitable etherifying agents are monofunctional alkyl or aryl halide, e.g. Ci-Ce-alkyl chloride, Ci-Ce-alkyl bromide, or Ci-Ce-alkyl iodide, preferably methyl chloride, or benzyl chloride, benzyl bromide, or benzyl iodide, or a mixture thereof.
- preferred end groups are halogen, in particular chlorine, alkoxy, in particular methoxy, aryloxy, in particular phenoxy, or benzyloxy.
- the hollow fiber membrane furthermore comprises a water- soluble polymer additive (A), wherein said additive (A) comprises polyvinylpyrrolidone (PVP).
- said additive (A) comprises polyvinylpyrrolidone (PVP).
- Polyvinylpyrrolidone is commercially available, e.g. Luvitec® from BASF SE.
- the PVP has a solution viscosity characterized by a K-value of at least 12 (PVP K12), of at least 17 (PVP K17), of at least 30 (PVP K30), of at least 80 (PVP K80), of at least 85 (PVP K85) or of at least 90 (PVP K90).
- the PVP has a solution viscosity characterized by a K-value of at least 80 (PVP K80), such as for example Luvitec® K80.
- the PVP has a solution viscosity characterized by a K-value of at least 85 (PVP K85), such as for example Luvitec® K85.
- PVP K85 solution viscosity characterized by a K-value of at least 85
- PVP K90 solution viscosity characterized by a K-value of at least 90
- the solution viscosity is determined according to the method of Fikentscher (Fikentscher, Cellu- losechemie 13, 1932 (58).
- the water-soluble additive (A) may furthermore comprise constituents selected from poly(alkylene oxides) and alcohols.
- suitable poly(alkylene oxides) are poly(ethylene oxide), polypropylene oxide) and poly(ethylene oxide)-poly(propylene oxide) copolymer.
- suitable alcohols are divalent alcohols or trivalent alcohols like glycerol.
- the water-soluble polymer additive (A) comprises at least 50% by weight, preferably at least 60% by weight, in particular at least 70% by weight of PVP in relation to the amount of additive (A) in the membrane.
- the water-soluble polymer additive (A) consists of polyvinylpyrrolidone as defined and preferably herein.
- the water-soluble polymer additive (A) consists of PVP, as defined and preferably herein, and at least one alcohol, preferably glycerol.
- the water-soluble polymer additive (A) contains 30 to 90% by weight of polyvinylpyrrolidone) and 10 to 70% by weight of at least one alcohol, preferably glycerol.
- the amount of PVP, as defined and preferably defined herein, in the hollow fiber membrane is preferably at least 10% by weight based on the total weight of the membrane, more specifically at least 11 % by weight, even more specifically at least 12% by weight. In a further embodiment, the amount of PVP in the hollow fiber membrane is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, the amount of PVP in the hollow fiber membrane is at least 16% by weight. In particular, PVP is present in an amount of 10 to 30% by weight, more specifically 10 to 20% by weight.
- This content is also called PVP to tai
- the present invention relates to the use of a hollow fiber membrane, comprising a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water- soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a humidifier, more specifically in a fuel cell membrane humidifier.
- P polymer
- A water- soluble polymer additive
- PVP polyvinylpyrrolidone
- the present invention relates to the use of a hollow fiber membrane, comprising a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
- the described hollow fiber membranes are particularly useful for humidifiers in polymer electrolyte membrane fuel cells.
- the present invention relates to a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water- soluble polymer additive (A) comprising at least 10 weight %, based on the total weight of the membrane, polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80.
- P polymer
- PVP polyvinylpyrrolidone
- PVP is present in an amount of at least 10% by weight based on the total weight of the membrane. This content is also called PVP to tai. More specifically, the amount of PVP in the inventive membrane is at least 11% by weight, even more specifically at least 12% by weight. In a further embodiment, the amount of PVP in the membrane is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, the amount of PVP in the membrane is at least 16% by weight. In particular, PVP is present in an amount of 10 to 30% by weight, more specifically 10 to 20% by weight.
- the inventive hollow fiber membrane and the hollow fiber membrane used according to the present invention comprises a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t).
- the person skilled in the art knows that the inner membrane surface layer (SLj n ) and/or the outer membrane surface layer (SL 0U t) serve(s) as the active separation layer(s).
- the supporting structure typically comprises pores.
- the minimal pore diameter of the supporting structure of the inventive hollow fiber membrane and the hollow fiber membrane used according to the invention may be ⁇ 10 nm and the supporting structure can have pore diameters up to 10 pm.
- the content of polyvinylpyrrolidone in the inner or in the outer membrane surface layer is at least 10 % by weight, based on the total weight of the membrane.
- the content of polyvinylpyrrolidone in the inner and the outer membrane surface layer is at least 10 weight%, based on the total weight of the membrane.
- the PVP content in the inner membrane surface layer (SLj n ) is at least 10% by weight, based on the total weight of the membrane.
- This content is also called PVPj n .
- PVPin is at least 11 % by weight, even more specifically at least 12% by weight.
- PVPj n is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight.
- PVPj n is at least 16% by weight.
- PVPj n may be 10 to 30% by weight, more specifically 10 to 20% by weight.
- the PVP content in the outer membrane surface layer is at least 10% by weight based on the total weight of the membrane.
- This content is also called PVP 0U t.
- PVP 0U t is at least 11% by weight, even more specifically at least 12% by weight.
- PVP 0U t is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight.
- PVP 0U t is at least 16% by weight.
- PVP 0U t may be 10 to 30% by weight, more specifically 10 to 20% by weight.
- the inventive hollow fiber membrane is characterized by exhibiting high water transfer rates while selectively withholding gas such as nitrogen.
- This combination of properties makes the inventive membranes particularly useful for the use in humidifies, in particular in fuel cell membrane humidifiers, where water vapor needs to selectively pass through the membrane.
- a gaseous exhaust composition is supplied to the fuel cell and undesired gas contained therein, such as, in particular nitrogen, needs to be withheld.
- gasses that may be contained in the gaseous composition supplied to the fuel cell are, for example, nitrogen, oxygen, carbon dioxide, carbon monoxide, noble gasses and/or ambient air.
- the hollow fiber membrane preferably has a water vapor transmission rate of at least 3.5 kg/h m 2 at 80 °C, more specifically of at least 3.6 kg/h m 2 at 80 °C, even more specifically of at least 3.7 kg/h m 2 at 80 °C at a water flux (WET-IN) of 10 g/ s m 2 .
- the hollow fiber membrane preferably has a water vapor transmission rate of at least 3.8 kg/h m 2 at 80 °C, more specifically of at least 3.9 kg/h m 2 at 80 °C, even more specifically of at least 4.0 kg/h m 2 at 80 °C at a water flux (WET-IN) of 10 g/ s m 2 .
- the hollow fiber membrane preferably has a nitrogen gas permeability of 3 L/m 2 h bar or lower at 2 bar, more specifically of 2.9 L/m 2 h bar or lower at 2 bar, even more specifically of 2.8 L/m 2 h bar or lower at 2 bar, measured before contact with water vapor.
- the hollow fiber membrane preferably has a nitrogen gas permeability of 2.7 L/m 2 h bar or lower at 2 bar, more specifically of 2.6 L/m 2 h bar or lower at 2 bar, even more specifically of 2.5 L/m 2 h bar or lower at 2 bar, measured before contact with water vapor.
- the hollow fiber membrane preferably has a nitrogen gas permeability of 2.4 L/m 2 h bar or lower at 2 bar, more specifically of 2.3 L/m 2 h bar or lower at 2 bar, even more specifically of 2.2 L/m 2 h bar or lower at 2 bar, measured before contact with water vapor.
- the hollow fiber membrane preferably has a nitrogen gas permeability of 2.1 L/m 2 h bar or lower at 2 bar, more specifically of 2.0 L/m 2 h bar or lower at 2 bar, even more specifically of 1.9 L/m 2 h bar or lower at 2 bar, measured before contact with water vapor.
- BET Brunauer-Emmet-Teller
- the hollow fiber membrane preferably has BET value of the surface of 32 m 2 /g or lower, in particular 31 m 2 /g or lower, more specifically 30 m 2 /g or lower. It may be preferred, if the BET value of the surface is 29 m 2 /g or lower, in particular 28 m 2 /g or lower.
- the BET surface is determined by gas-adsorption-desorption (GAD) experiments with nitrogen by 5-point method with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The samples are activated at 130 °C for 15 min before measurement
- a further aspect of the present invention is a method for the preparation of the inventive hollow fiber membrane, wherein the process comprises the steps: a) providing a solution (S) which comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80, and at least one solvent (D); b) passing the solution (S) through a spinneret and contacting the hollow fiber formed with at least one protic polar solvent, thereby forming the hollow fiber membrane; and c) isolating the hollow fiber membrane without carrying out a step of removal of the additive (A) from the membrane.
- S a solution
- P polymer
- A water-soluble polymer additive
- PVP polyvinylpyrrolidone
- D solvent
- a solution (S) comprising the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), as defined and preferably defined herein, a water-soluble polymer additive (A), and at least one solvent (D), wherein the water-soluble polymer additive (A) comprises polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80 as defined and preferably defined herein.
- PVP polyvinylpyrrolidone
- the solution (S) in step a) can be provided by any method known to the skilled person.
- the solution (S) can be provided in step a) in customary vessels that may comprise a stirring device and preferably a temperature control device.
- the solution (S) is provided by dissolving the polymer (P) and the water-soluble polymer additive (A) in the at least one solvent (D).
- Step a) is preferably carried out at elevated temperatures, especially in the range from 20 to 100 °C, more preferably in the range from 40 to 80 °C. A person skilled in the art will choose the temperature in accordance with the at least one solvent (D).
- the solution (S) preferably comprises the polymer (P) and the water-soluble polymer additive (A) completely dissolved in the at least one solvent (D). This means that the solution (S) preferably comprises no solid particles of the polymer (P) and the water-soluble polymer additive (A).
- the at least one polymer (P) used in the inventive process is selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and is defined and preferably defined above.
- the solution (S) may comprise from 1 to 50% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), in particular from 1 to 45% by weight, specifically from 5 to 40% by weight, more specifically from 8 to 35% by weight, based in each case on the total weight of the solution (S).
- P polymer selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone
- the water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80 is as defined and preferably defined above.
- the water-soluble polymer additive (A) comprises at least 50% by weight, preferably at least 60% by weight, in particular at least 70% by weight of PVP in relation to the total weight of additive (A) in the solution (A).
- the water-soluble polymer additive (A) consists of polyvinylpyrrolidone as defined and preferably defined above.
- the solution (S) comprises at least 3 % by weight, more specifically at least 4% by weight, even more specifically at least 4.5% by weight of the polyvinylpyrrolidone (PVP) with a solution viscosity characterized by a K-value of at least 80, based in each case on the total weight of the solution (S).
- the solution (S) may comprise 3 to 30% by weight, more specifically from 3 to 25% by weight, even more specifically from 3 to 20% by weight of the water-soluble polymer additive (A), based in each case on the total weight of the solution (S).
- the solution (S) comprises at least 4 % by weight, more specifically 4 to 30% by weight, even more specifically 5 to 30% by weight of the polyvinylpyrrolidone (PVP) with a solution viscosity characterized by a K-value of at least 80, based in each case on the total weight of the solution (S).
- PVP polyvinylpyrrolidone
- the water-soluble polymer additive (A) used in the process of the inventive comprises polyvinylpyrrolidone, but may also additionally comprise other suitable water-soluble additives such as, for example selected from poly(alkylene oxides) and alcohols.
- suitable poly(alkylene oxides) that may be comprised in the water-soluble polymer additive (A) are poly(ethylene oxide), polypropylene oxide) and poly(ethylene oxide)- polypropylene oxide) copolymer.
- suitable alcohols that may be comprised in the water-soluble polymer additive (A) are divalent alcohols or trivalent alcohols like glycerol.
- the water-soluble polymer additive (A) comprises 60 to 90% by weight of polyvinylpyrrolidone and from 10 to 40% by weight of at least one alcohol, preferably glycerol.
- the solution (S) comprises from 1 to 50% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), from 3 to 30% by weight of the water-soluble polymer additive (A) consisting of PVP as defined and preferably defined herein, and from 20 to 96% by weight of the at least one solvent (D), based in each case on the total weight of the solution (S).
- P polymer
- A water-soluble polymer additive
- D the at least one solvent
- the solution (S) comprises from 1 to 40% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), from 3 to 20% by weight of the water-soluble polymer additive (A) consisting of PVP as defined and preferably defined herein, and from 40 to 96% by weight of the at least one solvent (D), based in each case on the total weight of the solution (S).
- P polymer
- A water-soluble polymer additive
- D at least one solvent
- At least one solvent within the context of the present invention means precisely one solvent, and also a mixture of two or more solvents.
- the at least one solvent (D) can be any solvent known to the skilled person that is suitable for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and the water-soluble polymer additive (A).
- the at least one solvent (D) is soluble in water.
- the at least one solvent (D) is preferably selected from the group consisting of N- alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2- pyrrolidone and N-tert.-butyl-2-pyrrolidone, 2-pyrrolidone, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, N,N-dimethyl-2-hydroxypropan amide, N,N-diethyl-2-hydroxypropan amide, y-valerolactone, dihydrolevoglucosenone, methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate and sulfolane.
- N-alkyl-2-pyrrolidone, y-valerolactone and N,N-dimethyl-2- hydroxypropan amide are particularly preferred.
- N-methylpyrrolidone is
- the solution (S) can comprise, for example, in the range from 20 to 96% by weight of the at least one solvent (D), preferably in the range from 40 to 96% by weight of the at least one solvent (D), more preferably in the range from 50 to 70% by weight of the at least one solvent (D), based on the total weight of the solution (S).
- the percentages by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sul- fone), the water-soluble polymer additive (A) and the least one solvent (D). typically add up to 100 % by weight.
- the duration of step a) may vary between wide limits and is preferably in the range from 10 min to 48 h (hours), especially in the range from 10 min to 24 h, and more preferably in the range from 15 min to 12 h.
- a person skilled in the art will choose the duration of step a) so as to obtain a homogeneous solution of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and the water-soluble polymer additive (A) in the at least one solvent (D).
- step b) the solution (S) is passed through a spinneret and the hollow fiber formed is contacted with at least one protic polar solvent, thereby forming the hollow fiber membrane.
- step b) may be performed by extruding the solution (S) through an extrusion nozzle (also called spinneret) with the required number of hollow needles.
- the hollow fiber is preferably introduced into a liquid comprising at least one protic polar solvent.
- step b) Before carrying out step b), it is possible to filter solution (S) to obtain a filtered solution (S). Moreover, it is possible to degas the solution (S) before step b) is carried out.
- the degassing of the solution (S) can be carried out by any method known to the skilled person, for example, via vacuum or by allowing the solution (S) to rest.
- the single bore or multi-bore hollow fiber membrane is obtained by following a phase inversion process, which means that the composition of dissolved at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and water-soluble polymer additive (A) are transformed into a solid phase.
- a phase inversion process which means that the composition of dissolved at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and water-soluble polymer additive (A) are transformed into a solid phase.
- Phase inversion processes are in general known to the person skilled in the art.
- the phase inversion process can, for example, be performed by cooling down the solution, wherein the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) comprised in the solution precipitates.
- Another possibility to perform the phase inversion process is to bring the solution in contact with a gaseous liquid that is a non-solvent for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone).
- the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) will then as well precipitate.
- Suitable gaseous liquids that are non-solvents for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) are, for example, protic polar solvents described hereinafter in their gaseous state.
- Another phase inversion process which is preferred within the context of the present invention is the phase inversion by immersing the solution into at least one protic polar solvent. Therefore, according to step b) of the inventive process, the hollow fiber formed from the solution (S) is contacted with at least one protic solvent. This leads to the formation of the hollow fiber membrane.
- the hollow fiber is contacted with the at least one protic polar solvent by introducing the hollow fiber into a liquid comprising said at least one protic solvent.
- the liquid may be a bath, such as a coagulation bath.
- the at least one protic polar solvent is preferably a non-solvent for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone).
- Preferred at least one protic polar solvents are water, methanol, ethanol, n-propanol, iso-propanol, glycerol, ethylene glycol and mixtures thereof.
- the at least one protic polar solvent is a water-based coagulation liquid. Therefore, another object of the present invention is a method for the preparation of a hollow fiber membrane, wherein the at least one protic polar solvent in step c) is a water-based coagulation liquid.
- the water-based coagulation liquid may comprise further components besides water, such as, for example, the same solvent (D) as comprised in the solution (S) or an alcohol, such as, for example, glycerol.
- the at least one polar solvent used as coagulating liquid may also be injected through the hollow needles into the extruded polymer solution (S) during the step of passing the solution through the spinneret. Thereby, parallel continuous channels extending in extrusion direction are formed.
- the contacting with the at least one protic solvent is preferably carried out at a temperature in the range of 20 to 80°C, more preferably at a temperature in the range of 20 to 60°C.
- the at least one protic polar solvent in particular the water-based coagulation liquid, is held at a temperature in a range of 20 to 80°C, more preferably at a temperature in the range of 20 to 60°C.
- the coagulation liquid as defined above is injected through the hollow needles into the extruded polymer during extrusion.
- the extruded polymer membrane gets a hollow cylindrical geometry and parallel continuous channels extending in extrusion direction are formed in the extruded polymer.
- the formed hollow fiber is preferably brought in contact with water as coagulation agent.
- the parameters of the process like extrusion speed, temperature, nozzle geometry, type of coagulant, concentrations may have an effect on and thus can be used to control parameters such as the membrane’s shape and thickness and thus the performance of the membrane.
- Hollow fiber membranes can be optionally wound up onto rolls and/or bundled to bundles of hollow fibers.
- the hollow fiber membrane is isolated according to step c) without carrying out a step of removal of the additive (A) from the membrane.
- the inventive process also comprises a step of d) rinsing with a liquid comprising water, preferably at elevated temperatures such as 60 °C.
- the liquid consists of water.
- Step d) may be desired and can be optionally carried out to remove residual components from the membrane such as residual amounts of solvent D).
- the additive (A) in particular the polyvinylpyrrolidone (PVP) with a K-value of at least 80 contained therein, is not washed out in a substantial extent.
- the inventive process also comprises the step of e) drying the hollow fiber membrane.
- Drying can be carried out by any means known to the person skilled in the art of membranes.
- the present invention relates to a hollow fiber membrane obtainable by the inventive process as described herein.
- the obtained inventive hollow fiber membrane is essentially free from the at least one solvent (D). “Essentially free” within the context of the present invention means that the membrane comprises at most 1 % by weight, preferably at most 0.5 % by weight and particularly preferably at most 0.1 % by weight of the at least one solvent based on the total weight of the hollow fiber membrane.
- water vapor from the exhaust gas of the fuel cell reaction is used to be provided to the fuel cell membrane.
- the water vapor permeates through a membrane as selectively as possible to be provided to the polymeric electrolyte membrane.
- the hollow fiber membranes described herein in particular the membranes according to the present invention, can successfully be used as membrane in a humidifier in a fuel cell, because water vapor can pass through the humidifier membrane while gas contained in the gaseous mixture is withheld.
- the hollow fiber membranes have proven to be selectively gas-tight with respect to unwanted gas, such as for example nitrogen and that the membranes are effective at the operation temperatures of a fuel cell which is usually at 80 to 90 °C.
- the hollow fiber membranes described herein have shown to perform particularly well and selectively in this temperature range.
- the present invention thus relates to a separation element, a membrane module, a membrane cartridge or a separation system comprising the inventive hollow fiber membrane as described herein.
- Still a further object of the present invention is a humidifier comprising the inventive hollow fiber membrane as described herein, in particular a humidifier which is a fuel cell membrane humidifier.
- Still a further object of the present invention is a humidifier comprising a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), and wherein the membrane comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP).
- the humidifier is a fuel cell membrane humidifier.
- the present invention relates to a fuel cell comprising a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), and wherein the membrane comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP).
- P polymer
- A water-soluble polymer additive
- PVP polyvinylpyrrolidone
- the present invention relates to a fuel cell comprising the inventive hollow membrane as described herein.
- the present invention relates to a fuel cell comprising a separation element, membrane module, membrane cartridge or separation system comprising the inventive hollow fiber membrane as described herein.
- the present invention relates to a fuel cell comprising a humidifier, in particular a fuel cell membrane humidifier, wherein said humidifier comprises a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLj n ) and an outer membrane surface layer (SL 0U t), and wherein the membrane comprises at least one poly(arylene ether sulfone) polymer (P) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP).
- the present invention relates to a fuel cell comprising an inventive humidifier, in particular a fuel cell membrane humidifier as described herein.
- Luvitec® K90 Polyvinylpyrrolidone with a solution viscosity characterized by the K- value of 90, determined according to the method of Fikentscher (Fikentscher, Cellulosechemie 13, 1932 (58))
- the polymer solution turbidity was measured with a turbidimeter 2100AN (Hach Lange GmbH, Dusseldorf, Germany) employing a filter of 860 nm at 60 °C and expressed in nephelometric turbidity units (NTU). NTU values below 1 are preferred.
- the water vapor transmission rate (WTR, g/s m 2 ) was tested on mini modules comprising 8 to 10 hollow fibers of 10 cm length. Also, the nitrogen permeability (L/m 2 h bar) at a pressure of 2 bar was assessed before and after WTR measurements at 80 and 90 °C. A high WTR in combination with low nitrogen leakage is desired.
- the polymer solution viscosity was measured with a Brookfield Viscometer DV-I Prime (Brookfield Engineering Laboratories, Inc. Middleboro, USA) with RV 6 spindle at 60 °C with 20 rpm.
- PVP content was measured with a Brookfield Viscometer DV-I Prime (Brookfield Engineering Laboratories, Inc. Middleboro, USA) with RV 6 spindle at 60 °C with 20 rpm.
- the polyvinylpyrrolidone (PVP) content of the membranes was determined by dissolving the membrane sample in N,N-dimethylformamide (DMF) and casting the solution as film on KRS-5 windows of thalliumbromiodide. The films were dried at 160 °C and analyzed with a Ni- colet 6700 FT-IR spectrometer (Thermo Fischer Scientific, Waltham, Massachusetts, USA). Together with calibration samples of known polyvinylpyrrolidone content, the adsorption band at 1680 cm -1 was used to determine the overall polyvinylpyrrolidone content of the membrane samples.
- the polyvinylpyrrolidone content of the inner membrane surface layer and outer membrane surface layer was estimated with the same adsorption band by attenuated infrared spectroscopy (ATR) and reference samples.
- Solvent exchanged and dried membrane samples were used for Brunauer-Emmet-Teller (BET) surface assessment.
- the wet membrane samples were stored for 12 h subsequently in wa- ter/ethanol (1 :1 wt/wt), water/ethanol (1 :2 wt/wt), ethanol/n-hexane (1 :1 wt/wt) and finally n- hexane before drying at 60 °C under vacuum.
- the BET surface was determined by gas- adsorption-desorption (GAD) experiments with nitrogen by 5-point method with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The samples were activated at 130 °C for 15 min before measurement.
- GID gas- adsorption-desorption
- a clear viscous solution containing 19 wt% membrane polymer and 5 wt% polyvinylpyrrolidone in 76 wt% NMP was prepared using a Speed- Mixer® DAC 600.1 Vac-P (Hauschild & Co. KG, Hamm, Germany) at speeds of 200, 800 and 1200 rpm within 30 minutes of mixing. The solution was degassed overnight at room temperature.
- a hollow fiber membrane was formed by reheating the polymer solution at 60°C for 2 hours and passing the solution as well as the center fluid through a spinning die.
- the diameter of the spinning die was 0.33 mm - 0.62 mm - 1.3 mm.
- the temperature of the die was 60° C.
- the hollow fiber was formed at a spinning speed of 13 cm/min.
- the polymer solution leaving the die with 3.0 ml/min while the center fluid was leaving the die with 3.3 ml/min.
- the liquid capillary was passed into a water bath having a temperature of 24° C.
- the distance between the die and the precipitation bath was 13 cm.
- the hollow fiber membrane formed was guided through one water bath and subsequently was wound onto a winding reel. Afterwards the membrane was directly dried (treatment A) or treated with 2000 ppm aqueous sodiumhypochlorite (NaOCI) at pH 9.5 for 3 hours and 20 hours water extraction at 80 °C with subsequent drying (post treatment B).
- Table 1 Composition and properties of humidifier membranes prepared from a blend of PAES and PVP (PVP K90).
- Table 3 Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); nitrogen permeability at 2 bar pressure.
- Table 4 Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); water transmission rate (WTR, kg/ h m 2 ) at 80 °C at a given water flux (WET-IN, g/ s m 2 ).
- Table 5 Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); water transmission rate (WTR, kg/ h m 2 ) at 90 °C at a given water flux (WET-IN, g/ s m 2 ).
- the hollow fiber membranes according to the invention show a particularly low gas leakage of ⁇ 10 L/m 2 h bar (table 3), and, at the same time, have high water transmission rates (WTR rates) at temperatures of 80 and 90 °C at all relevant water flux values (tables 4 and 5).
- WTR rates water transmission rates
- the post treated open porous hollow fiber M-2B shows higher WTR rates but significantly higher nitrogen leakage, which makes it useless for fuel cell membrane humidifiers.
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Abstract
The present invention relates to a hollow fiber membrane made from blends of poly(aryl ether sulfone) and a water-soluble polymer additive, manufacturing methods therefor and their uses.
Description
Hollow fiber membranes comprising a poly(aryl ether sulfone) and a water-soluble polymer additive
The present invention relates to a hollow fiber membrane made from blends of poly(aryl ether sulfone) and a water-soluble polymer additive, manufacturing methods therefor and their uses. Furthermore, the present invention relates to a separation element, membrane module, separation system, membrane cartridge and fuel cell membrane humidifier containing such membrane or membranes.
In a hydrogen fuel cell, electricity is generated from the reaction of hydrogen and oxygen thereby forming water. In particular, polymer electrolyte membrane (PEM) fuel cells (FC) are used for carbon dioxide emission free transportation applications, wherein ambient air serves as source of oxygen necessary for the fuel cell reaction. For efficient operation and performance of the fuel cell, PEM membranes require a constant humidification at a predetermined level. Therefore, gas-to-gas humidifiers are used to transfer water vapor from the cathode exhaust gases to the intake gas. To provide for humidification, for example lightweight and miniaturized membrane humidifiers are used, wherein the humidifier may contain a hollow fiber membrane and selectively provides water vapor to the fuel cell membrane.
Various materials are being used for hollow fiber membranes. Examples are perfluorinated sulfonic acid polymers (PFSA) (e.g. Nation®, DuPont), polyimides or polyarylsulfones such as polyethersulfone (PESLI) or polysulfone (PSU). LIS2021154624 A1 is directed to a composite hollow fiber membrane including a hollow fiber membrane and a pollutant entrapping layer coated on the inner surface of the hollow fiber membrane, wherein the membrane can be used in a membrane humidifier for a fuel cell. From environmental standpoints, halogen-containing polymeric membrane material is unfavorable.
For the manufacturing process of polyarylsulfone-based hollow fibers by non-solvent induced phase separation (NIPS) processing, hydrophilic water-soluble polymers such as polyvinylpyrrolidone (PVP) are used as additives to adjust the viscosity of the polymer solution. Such additives may also act as place holders for pores in the filtration layer of the hollow fiber membranes (e.g. S. Munari, Desalination 1988, 70, 265-275). In a subsequent post treatment step the filtration layer is formed by removal of the hydrophilic polymer from the polyarylsulfone matrix. It can selectively be removed by chemical treatment with hypochlorite (I. M. Wienk et.al, Journal Polymer Science: Part A: Polymer Chemistry 1995, 33, 49-54).
With the increasing demand for environmentally friendly provision of electricity, there is need for optimized fuel cell assemblies including membrane humidifiers for efficient and long-lasting operation of the fuel cell.
Consequently, an object of the invention was finding a suitable membrane for fuel cell humidifiers that can selectively withhold gas and transmit water vapor to the fuel cell membrane. A further object was the provision of a selective and halogen-free free membrane with high water vapor transmission useful in fuel cell membrane humidifiers.
This object is achieved with the use of a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a poly(arylene ether sulfone) and a sulfonated poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a fuel cell membrane humidifier and the use of such membrane for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
Furthermore, within the framework of the present invention, it has been surprisingly found that the inventive hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a poly(arylene ether sulfone) and a sulfonated poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising at least 10 % by weight, based on the total weight of the membrane, polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80, exhibits high water transfer rates while selectively withholding undesired gas contained in the gaseous exhaust composition supplied to the fuel cell. The inventive membranes and assemblies containing the inventive membranes are particularly useful for humidifiers in polymer electrolyte membrane fuel cells.
In the context of the present invention, the term “membrane” means a semipermeable structure acting as a selective barrier, allowing some particles, substances or chemicals to pass through, while retaining others. In general, membranes are applied in various liquid and gaseous separations.
The membrane of the present invention is a hollow fiber membrane, wherein it may be a single bore hollow fiber or multiple bore hollow fiber membrane. In a hollow fiber membrane, a semipermeable barrier is in the form of a hollow fiber.
Multiple channel membranes, also referred to as multi bore membranes, comprise more than one longitudinal channel, also referred to as “channel” or “bore”.
The number of channels is typically 2 to 19. In one embodiment, the multiple bore hollow fiber membrane comprises two or three channels. In another embodiment, the multiple bore hollow fiber membrane comprises 5 to 9 channels. In one specific embodiment, the multiple bore hollow fiber membrane comprises seven channels. In yet another embodiment, the multiple bore hollow fiber membrane comprises 20 to 100 channels.
The shape of the bore or bores may vary. Normally, the membranes according to the invention have an essentially circular, ellipsoid or rectangular diameter. Preferably, membranes according to the invention are essentially circular, i.e. the bores have an essentially circular diameter.
In another embodiment, such bores have an essentially ellipsoid diameter. In yet another embodiment, channels have an essentially rectangular diameter. In some cases, the actual form of such channels may deviate from the idealized circular, ellipsoid or rectangular form.
The hollow fiber membrane channels have an inner and an outer diameter. The difference of the outer diameter and the inner diameter is the thickness of the hollow fiber membrane.
Normally, such channels have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 0.05 mm to 3 mm, preferably 0.5 to 2 mm, more preferably 0.9 to 1.5 mm. In another preferred embodiment, such channels have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) in the range from 0.2 to 0.9 mm.
In one preferred embodiment, hollow fiber membranes according to the invention or used according to the invention have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 2 to 10 mm, preferably 3 to 8 mm, more preferably 4 to 6 mm.
In another preferred embodiment, hollow fiber membranes according to the invention or used according to the invention have an outer diameter (for essentially circular diameters), an outer smaller diameter (for essentially ellipsoid diameters) or an outer smaller feed size (for essentially rectangular diameters) of 2 to 4 mm.
The hollow fiber membrane can have any thickness. For example, the thickness of the membrane is in the range from 20 to 150 pm, preferably in the range from 20 to 100 pm and most preferably in the range from 30 to 60 pm.
If multi-bore hollow fiber membranes contain channels with an essentially rectangular shape, these channels can be arranged in a row. If the channels in a multi-bore hollow fiber membrane have essentially circular shape, these channels are preferably arranged such that a central channel is surrounded by the other channels. In one preferred embodiment, a membrane comprises one central channel and for example four, six or 18 further channels arranged cyclically around the central channel. The wall thickness in such multiple channel membranes is normally from 0.02 to 1 mm at the thinnest position, preferably 30 to 500 pm, more preferably 100 to 300 pm.
The inventive hollow fiber membrane and the hollow fiber membrane used according to the invention, respectively, comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone). The poly(arylene ether sulfone) is non-sulfonated if it is not explicitly mentioned.
Poly(arylene ether sulfone) polymers belong to the group of high temperature resistant polymers showing high heat resistance, excellent mechanical performance and inherent flame re- tardancy (E.M. Koch, H.-M. Walter, Kunststoffe 80 (1990) 1146; E. Ddring, Kunststoffe 80, (1990) 1149, N. Inchaurondo-Nehm, Kunststoffe 2008 190). Polyarylene(ether)sulfones are generally known to a person skilled in the art.
“Non-sulfonated” within the context of the present invention means that the poly(arylene ether sulfone) polymer does not comprise any -SO2X group, wherein X is selected from the group consisting of Cl’ and O’ combined with one cation equivalent. “One cation equivalent” within the context of the present invention means one cation of a single positive charge or one charge equivalent of a cation with two or more positive charges, for example, H+, Li+, Na+, K+, Mg2+, Ca2+ or NH4 +.
The term “a sulfonated poly(arylene ether sulfone)” or “a poly(arylene ether sulfone)”, respectively, in the present application is understood to mean exactly one sulfonated poly(arylene ether sulfone) polymer or poly(arylene ether sulfone) polymer, respectively, and also mixtures of two or more sulfonated poly(arylene ether sulfone) polymers or of two or more poly(arylene ether sulfone) polymers, respectively.
According to one embodiment, the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention, respectively, comprises a poly(arylene ether sulfone) polymer (P) as defined or preferably defined herein. In one specific embodiment thereof, the hollow fiber membrane does not contain any sulfonated poly(arylene ether sulfone).
According to these embodiments, the hollow fiber membrane comprises preferably at least 50 % by weight of the poly(arylene ether sulfone) polymer (P), more preferably at least 60 % by weight and most preferably at least 70 % by weight of the poly(arylene ether sulfone) polymer (P) based on the total weight of the hollow fiber membrane.
According to a further embodiment, the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention, respectively, comprises a sulfonated poly(arylene ether sulfone) polymer (P) as defined or preferably defined herein. In a specific embodiment thereof, the hollow fiber membrane does not contain any (non-sulfonated) poly(arylene ether sulfone).
According to these embodiments, the hollow fiber membrane comprises preferably at least 50 % by weight of the sulfonated poly(arylene ether sulfone) polymer (P), more preferably at
least 60 % by weight and most preferably at least 70 % by weight of the sulfonated poly(arylene ether sulfone) polymer (P) based on the total weight of the hollow fiber membrane.
According to still a further embodiment, the hollow fiber membrane of the invention or the hollow fiber membrane used according to the invention, respectively, comprises a sulfonated poly(arylene ether sulfone) as defined or preferably defined herein and a poly(arylene ether sulfone) as defined or preferably defined herein.
If both, the sulfonated and non-sulfonated poly(arylene ether sulfone) is contained in the hollow fiber membrane, the hollow fiber membrane preferably comprises from 5 to 90% by weight, more preferably from 7.5 to 80% by weight, of the sulfonated poly(arylene ether sulfone) polymer (P), based on the total weight of the membrane. The membrane also preferably comprises from 10 to 95% by weight, more preferably from 20 to 92.5% by weight, of the poly(arylene ether sulfone) polymer (P), based on the total weight of the membrane.
Therefore, in a preferred embodiment, the hollow fiber membrane comprises from 5 to 90% by weight of the sulfonated poly(arylene ether sulfone) polymer and from 10 to 95% by weight of the poly(arylene ether sulfone) polymer, based in each case on the total weight of the membrane.
In a preferred embodiment, the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (I)
wherein the definitions of the symbols t, q, Q, T, Y, Ar and Ar1 are as follows: t, q independently of one another 0, 1 , 2 or 3;
Q, T, Y independently of one another a chemical bond or a group selected from -O-, -S-, -SO2-, S=O, C=O, -N=N- and -CRaRb-, wherein Ra and Rb independently of one another are a hydrogen atom, (Ci-Ci2)alkyl, (Ci-Ci2)alkoxy, (C3-Ci2)cycloalkyl or a (C6-Cis)aryl group, and wherein at least one of Q, T, and Y is present and is -SO2-; and
Ar and Ar1 independently of one another (C6-Cis)arylene; and where at least one unit (I) comprises an arylene group which is substituted with at least one -SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H+, Li+, Na+, K+, Mg2+, Ca2+ or NHY.
If Q, T or Y, among the abovementioned conditions, is a chemical bond, this is understood to mean that the adjacent group to the left and the adjacent group to the right are bonded directly to one another via a chemical bond. It will be readily appreciated that at least one of the groups consisting of Q, T and Y being -SO2- means that at least one group in formula (I) is -SO2-. Thus, when q is = 0, at least one of T and Y is -SO2-; when, for example, t is = 0, at least one of Q and Y is -SO2- and when q = 0 and t = 0 then Y is SO2.
According to one preferred embodiment, t and q are independently 0 or 1.
According to one preferred embodiment, Q, T, and Y in formula II are independently selected from a chemical bond, -O-, -SO2- and -CRaRb-, with the proviso that at least one of Q, T, and Y is present and is -SO2-. Furthermore, it may be preferred, if Ra and Rb are, independently of one another, hydrogen or (Ci-C4)alkyl.
In -CRaRb-, Ra and Rb are preferably independently selected from hydrogen, (Ci-Ci2)alkyl, (C1- Ci2)alkoxy and (Ce-Cisjaryl.
(Ci-Ci2)alkyl refers to linear or branched saturated hydrocarbon groups having from 1 to 12 carbon atoms. The following moieties are particularly encompassed: (Ci-Ce)alkyl, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, 2- or 3-methylpentyl, as well as (C?-Ci2)alkyl, e.g. unbranched heptyl, octyl, nonyl, decyl, undecyl, lauryl, and the singly branched or multibranched analogs thereof.
The term " Ci-Ci2-alkoxy" refers to a linear or branched alkyl group having 1 to 12 carbon atoms which is bonded via an oxygen, at any position in the alkyl group, e.g. methoxy, ethoxy, n- propoxy, 1 -methylethoxy, butoxy, 1-methyhpropoxy, 2-methylpropoxy or 1 ,1 -dimethylethoxy.
(C3-Ci2)cycloalkyl refers to monocyclic saturated hydrocarbon radicals having 3 to 12 carbon ring members and particularly comprises (Cs-Csjcycloalkyl, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylethyl, -propyl, -butyl, -pentyl, -hexyl, cyclohexylmethyl, -dimethyl, and -trimethyl.
Ar and Ar1 are independently of one another a (C6-Cis)-arylene group. It may be preferred that, according to a specific embodiment, Ar1 is an unsubstituted (Ce-Ci2)arylene group.
It may be preferred that Ar and Ar1 are independently selected from phenylene, bisphenylene and naphthylene groups, and from arylene groups that derive from anthracene, from phenanthrene, or from naphthacene. For examples, Ar and Ar1 are independently selected from 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4-phenylene, 1 ,6-naphthylene, 1 ,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.
In particular, it may be preferred that Ar and Ar1 are independently selected from phenylene and naphthylene groups, such as independently selected from 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4- phenylene, 1 ,6-naphthylene, 1 ,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, more specifically independently selected from 1 ,4-phenylene, 1 ,3-phenylene and naphthylene. Further- more, according to another embodiment of the present invention Ar and Ar1 are independently selected from arylene groups that derive from anthracene, from phenanthrene, or from naphthacene. According to still a further embodiment, Ar and Ar1 are independently selected from 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.
Preferred sulfonated poly(arylene ether sulfone) polymers are those comprising at least one of the following units la to Io as repeat structural units, wherein at least one unit (I) comprises an arylene group which is substituted with at least one -SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H+, Li+, Na+, K+, Mg2+, Ca2+ or NH4 +:
In addition to the preferred units la to Io, preference is also given to those units in which one or more 1 ,4-phenylene units which originate from hydroquinone are replaced by 1 ,3-phenylene units which originate from resorcinol or by naphthylene units which originate from dihydroxynaphthalene.
Particularly preferred units of the general formula (I) are the units la, Ig and Ik. It is also particularly preferred when the sulfonated poly(arylene ether sulfone) polymers are formed essentially from one kind of units of the general formula (I), especially from a unit selected from la, Ig and Ik.
In a particularly preferred embodiment, Ar = 1 ,4-phenylene, t = 1 , q = 0, T is a chemical bond and Y = SO2. Particularly preferred sulfonated poly(arylene ether sulfone) polymers (A) formed from the aforementioned repeat unit are referred to as sulfonated polyphenylene sulfone (PPSU) (formula Ig).
In a further particularly preferred embodiment, Ar = 1 ,4-phenylene, t = 1 , q = 0, T = C(CH3)2 and Y = SO2. Particularly preferred sulfonated poly(arylene ether sulfone) polymers (A) formed from the aforementioned repeat unit are referred to as sulfonated polysulfone (PSU) (formula la).
In a further particularly preferred embodiment, Ar = 1 ,4-phenylene, t = 1 , q = 0, T = Y = SO2. Particularly preferred sulfonated poly(arylene ether sulfone) polymers (A) formed from the aforementioned repeat unit are referred to as sulfonated poly(ether sulfone) (PESLI) (formula Ik).
Abbreviations such as PPSLI, PESLI and PSU in the context of the present invention conform to DIN EN ISO 1043-1 (Plastics - Symbols and abbreviated terms - Part 1 : Basic polymers and their special characteristics (ISO 1043-1 :2001); German version EN ISO 1043-1 :2002).
In a preferred embodiment, the sulfonated poly(arylene ether sulfone) polymer is a copolymer formed from poly(ether sulfone) (PESLI) units and poly(phenylene sulfone) (PPSLI) units, wherein at least one unit comprises an arylene group which is substituted with at least one - SO2X group, wherein X is selected from the group consisting of Cl and O' combined with one cation equivalent, where the cation equivalent is H+, Li+, Na+, K+, Mg2+, Ca2+ or NH4 +. This copolymer may, for example, be a random copolymer or a block copolymer. Preference is given to a random copolymer formed from poly(ether sulfone) (PESLI) and poly(phenylene sulfone) (PPSLI) for the reason that a more homogenous material is obtained which shows no or little phase separation in the dissolved or solid state.
In case the sulfonated poly(arylene ether sulfone) polymer is a copolymer formed from poly(ether sulfone) (PESLI) units and poly(phenylene sulfone) (PPSLI) units, the sulfonated poly(arylene ether sulfone) polymer comprises in the range from 1 to 20 mol% of poly(phenylene sulfone) (PPSLI) units and from 80 to 99 mol% of poly(ether sulfone) (PESLI) units, in each case based on the total sum of all repeating units.
In a particularly preferred embodiment, the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (III)
In a further particularly preferred embodiment, the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (V)
It is also possible that the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (III) and/or formula (IV) and/or formula (V).
The sulfonated poly(arylene ether sulfone) polymer preferably has a number-average molecular weight (MN) of from 10 000 to 35 000 g/mol, determined by gel permeation chromatography in dimethylacetamide as solvent versus narrowly distributed polymethyl methacrylate as standard.
In addition, the sulfonated poly(arylene ether sulfone) polymer preferably has a content of free acid of less than 3 mg KOH/g sulfonated poly(arylene ether sulfone) polymer, determined by titration with 0.1 mol/l tetrabutylammoniumhydroxide solution (TBAH, in methanol/toluene) against a Solvotrode electrode (Metrohm).
The sulfonated poly(arylene ether sulfone) polymer can be prepared by any method known to the person skilled in the art.
Preferably, the sulfonated poly(arylene ether sulfone) polymer is produced by treating a respective non-sulfonated poly(arylene ether sulfone) polymer with at least one sulfonating agent. The at least one sulfonating agent is suitably any compound known to a person skilled in the art that is capable of introducing at least one SO2X group, where X is Cl or O', combined with one cation equivalent, where the cation equivalent is H+, Li+, Na+, K+, Mg2+, Ca2+ or NH4 +, into an aromatic ring of the non-sulfonated poly(arylene ether sulfone) polymer. The SO2X group is preferably a sulfonic acid group (-SO3H) or a group capable of reacting with water to form a sulfonic acid group. Groups of this type are known to a person skilled in the art and include, for example, chlorosulfonyl groups (-SO2CI). The SO2X group is more preferably therefore a sulfonic acid group (-SO3H) or a chlorosulfonyl group (-SO2CI), most preferably the SO2X group is a sulfonic acid group (-SO3H).
The reaction of the non-sulfonated poly(arylene ether sulfone) polymer with the at least one sulfonating agent preferably sulfonates at least one of the aromatic rings of the non-sulfonated poly(arylene ether sulfone) polymer at least partially.
The mechanism of the sulfonation reaction is known as such to a person skilled in the art. Thereby it is particularly preferable for the sulfonation reaction to replace a hydrogen atom of the aromatic ring by a sulfonic acid group (-SO3H).
Typically, from 0.001 to 1 , preferably from 0.005 to 0.1 and more preferably from 0.01 to 0.08 SO2X groups per aromatic ring is introduced into the non-sulfonated poly(arylene ether sulfone) polymer. The sulfonated poly(arylene ether sulfone) polymer therefore typically has from 0.001 to 1 , preferably from 0.005 to 0.1 , and more preferably from 0.01 to 0.08 sulfonic acid groups per aromatic ring.
The number of SO2X groups per aromatic ring is determined by averaging over all the aromatic rings of the sulfonated poly(arylene ether sulfone) polymer. To this end, the number of SO2X groups in the sulfonated poly(arylene ether sulfone) polymer is divided by the number of aromatic rings in the sulfonated poly(arylene ether sulfone) polymer. Methods of determining the number of SO2X groups and the number of aromatic rings, each in the sulfonated poly(arylene ether sulfone) polymer, are known to a person skilled in the art. The number of SO2X groups is determinable, for example, by acid-base titration or by spectroscopic methods such as H1NMR spectroscopy or IR spectroscopy (infrared spectroscopy). Sulfonated aromatic polymers having SO2X groups on the aromatic ring display characteristic peaks and bands, making it possible to determine the number of SO2X groups per aromatic ring in the sulfonated poly(arylene ether sulfone) polymer. The ratio of sulfonated to non-sulfonated aromatic rings can also be determined by these methods, in particular by H1NMR spectroscopy.
It may be preferred that the (non-sulfonated) poly(arylene ether sulfone) polymer is composed of units of the general formula (I)
wherein the definitions of the symbols t, q, Q, T, Y, Ar and Ar1 are as follows: t, q independently of one another 0, 1 , 2 or 3;
Q, T, Y independently of one another a chemical bond or a group selected from -O-, -S-,
-SO2-, S=O, C=O, -N=N- and -CRaRb-, wherein Ra and Rb independently of one another are a hydrogen atom, (Ci-Ci2)alkyl, (Ci-Ci2)alkoxy, (C3-Ci2)cycloalkyl or a (C6-Cis)aryl group, and wherein at least one of Q, T, and Y is present and is -SO2-; and
Ar and Ar1 independently of one another (C6-Cis)arylene.
If, within the abovementioned preconditions, Q, T or Y is a chemical bond, this means that the adjacent group on the left-hand side and the adjacent group on the right-hand side are present with direct linkage to one another via a chemical bond.
According to one preferred embodiment, t and q are independently 0 or 1.
According to one preferred embodiment, Q, T, and Y in formula II are independently selected from a chemical bond, -O-, -SO2- and -CRaRb-, with the proviso that at least one of Q, T, and Y is present and is -SO2-. Furthermore, it may be preferred, if Ra and Rb are, independently of one another, hydrogen or (Ci-C4)alkyl.
In -CRaRb-, Ra and Rb are preferably independently selected from hydrogen, (Ci-Ci2)alkyl, (Ci- Ci2)alkoxy and (C6-Cis)aryl.
The terms (Ci-Ci2)alkyl, " Ci-Ci2-alkoxy", (C3-Ci2)cycloalkyl, Ar and Ar1 are defined and preferably defined above.
Poly(arylene ether sulfone) polymers comprising at least one of the units la to Io as defined above as repeat structural units may be preferred.
Other repeat units, in addition to the units la to Io that may preferably be present, are those in which one or more 1 ,4-phenylene units deriving from hydroquinone have been replaced by 1 ,3-phenylene units deriving from resorcinol, or by naphthylene units deriving from dihydroxynaphthalene.
Units of the general formula (I) that are particularly preferred are the units la, Ig, and/or Ik. According to a specific embodiment, it is particularly preferred that the poly(arylene ether sulfone) polymer is in essence composed of one type of unit of the general formula (I), whereby said one type may particularly be selected from la, Ig, and Ik.
According to a preferred embodiment, the poly(arylene ether sulfone) polymer is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T is a chemical bond, and Y is SO2. This poly(arylene ether sulfone) is also termed polyphenylene sulfone (PPSU) (formula Ig).
According to a further preferred embodiment, the poly(arylene ether sulfone) polymer is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T is C(CH3)2, and Y is SO2. This poly(arylene ether sulfone) is also termed polysulfone (PSU) (formula la).
According to still a further preferred embodiment, the poly(arylene ether sulfone) polymer (P) is composed of repeat units where Ar is 1 ,4-phenylene, t is 1 , q is 0, T and Y are SO2. This poly(arylene ether sulfone) is also termed polyether sulfone (PESU) (formula Ik).
For the purposes of the present disclosure, abbreviations such as PPSU, PESU, and PSU are in accordance with DIN EN ISO 1043-1 :2001.
The weight-average molar masses Mw of the poly(arylene ether sulfone) polymer (P) are preferably from 10 000 to 40 000 g/mol, more specifically from 10 000 to 37 000 g/mol, in particular from 12 000 to 35 000 g/mol, particularly preferably from 14 000 to 33 000 g/mol, determined by means of gel permeation chromatography in dimethylacetamide as solvent against narrowly distributed polymethyl methacrylate as standard.
Production processes that lead to the abovementioned poly(arylene ether sulfone) polymers are known per se to the person skilled in the art and are described by way of example in Herman F. Mark, "Encyclopedia of Polymer Science and Technology", third edition, volume 4, 2003, chapter “Polsulfones” pages 2 to 8, and also in Hans R. Kricheldorf, "Aromatic Polyethers" in:
Handbook of Polymer Synthesis, second edition, 2005, pages 427 to 443.
The synthesis of the poly(arylene ether sulfone) polymers can generally be done by polycondensation of appropriate monomers in dipolar-aprotic solvents at elevated temperatures (R.N. Johnson et.al., J. Polym. Sci. A-1 5 (1967) 2375, J.E. McGrath et.al., Polymer 25 (1984) 1827).
The known poly(arylene ether sulfone) polymers usually have halogen end groups, in particular -F or -Cl, or phenolic OH end groups or phenolate end groups, where the latter can be present as such or in reacted form, in particular in the form of -OCH3 end groups.
Particular preference is given to the reaction, in aprotic polar solvents and in the presence of anhydrous alkali metal carbonate, in particular sodium carbonate, potassium carbonate, calcium carbonate, or a mixture thereof, very particularly preferably potassium carbonate, between at least one aromatic compound having two halogen substituents and at least one aromatic compound having two functional groups reactive toward abovementioned halogen substituents. One particularly suitable combination is N-methyl-2-pyrrolidone as solvent and potassium carbonate as base.
It is preferable that the poly(arylene ether sulfone) polymers have either halogen end groups, in particular chlorine end groups, or etherified end groups, in particular alkyl ether end groups, these being obtainable via reaction of the OH or, respectively, phenolate end groups with suitable etherifying agents. Examples of suitable etherifying agents are monofunctional alkyl or aryl halide, e.g. Ci-Ce-alkyl chloride, Ci-Ce-alkyl bromide, or Ci-Ce-alkyl iodide, preferably methyl chloride, or benzyl chloride, benzyl bromide, or benzyl iodide, or a mixture thereof. For the purposes of the polyarylene(ether)sulfones of component A) preferred end groups are halogen, in particular chlorine, alkoxy, in particular methoxy, aryloxy, in particular phenoxy, or benzyloxy.
According to the present invention, the hollow fiber membrane furthermore comprises a water- soluble polymer additive (A), wherein said additive (A) comprises polyvinylpyrrolidone (PVP).
Polyvinylpyrrolidone is commercially available, e.g. Luvitec® from BASF SE. According to one embodiment, the PVP has a solution viscosity characterized by a K-value of at least 12 (PVP K12), of at least 17 (PVP K17), of at least 30 (PVP K30), of at least 80 (PVP K80), of at least 85 (PVP K85) or of at least 90 (PVP K90). Preferably, the PVP has a solution viscosity characterized by a K-value of at least 80 (PVP K80), such as for example Luvitec® K80. In a further preferred embodiment, the PVP has a solution viscosity characterized by a K-value of at least 85 (PVP K85), such as for example Luvitec® K85. Particularly preferred is PVP having a solution viscosity characterized by a K-value of at least 90 (PVP K90), such as for example Luvitec® K90.
The solution viscosity is determined according to the method of Fikentscher (Fikentscher, Cellu- losechemie 13, 1932 (58).
The water-soluble additive (A) may furthermore comprise constituents selected from poly(alkylene oxides) and alcohols. Examples for suitable poly(alkylene oxides) are poly(ethylene oxide), polypropylene oxide) and poly(ethylene oxide)-poly(propylene oxide) copolymer. Examples for suitable alcohols are divalent alcohols or trivalent alcohols like glycerol.
Preferably, the water-soluble polymer additive (A) comprises at least 50% by weight, preferably at least 60% by weight, in particular at least 70% by weight of PVP in relation to the amount of additive (A) in the membrane.
In a preferred embodiment, the water-soluble polymer additive (A) consists of polyvinylpyrrolidone as defined and preferably herein.
According to a further embodiment, the water-soluble polymer additive (A) consists of PVP, as defined and preferably herein, and at least one alcohol, preferably glycerol. In particular, the water-soluble polymer additive (A) contains 30 to 90% by weight of polyvinylpyrrolidone) and 10 to 70% by weight of at least one alcohol, preferably glycerol.
The amount of PVP, as defined and preferably defined herein, in the hollow fiber membrane is preferably at least 10% by weight based on the total weight of the membrane, more specifically at least 11 % by weight, even more specifically at least 12% by weight. In a further embodiment, the amount of PVP in the hollow fiber membrane is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, the amount of PVP in the hollow fiber membrane is at least 16% by weight. In particular, PVP is present in an amount of 10 to 30% by weight, more specifically 10 to 20% by weight.
This content is also called PVPtotai
According to one aspect, the present invention relates to the use of a hollow fiber membrane, comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water- soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a humidifier, more specifically in a fuel cell membrane humidifier.
According to another aspect, the present invention relates to the use of a hollow fiber membrane, comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
In particular, the described hollow fiber membranes are particularly useful for humidifiers in polymer electrolyte membrane fuel cells.
According to still another aspect, the present invention relates to a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water- soluble polymer additive (A) comprising at least 10 weight %, based on the total weight of the membrane, polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80.
In the inventive membrane, PVP is present in an amount of at least 10% by weight based on the total weight of the membrane. This content is also called PVPtotai. More specifically, the amount of PVP in the inventive membrane is at least 11% by weight, even more specifically at least 12% by weight. In a further embodiment, the amount of PVP in the membrane is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, the amount of PVP in the membrane is at least 16% by weight. In particular, PVP is present in an amount of 10 to 30% by weight, more specifically 10 to 20% by weight.
The inventive hollow fiber membrane and the hollow fiber membrane used according to the present invention comprises a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut).
The person skilled in the art knows that the inner membrane surface layer (SLjn) and/or the outer membrane surface layer (SL0Ut) serve(s) as the active separation layer(s). The supporting structure typically comprises pores. The minimal pore diameter of the supporting structure of the inventive hollow fiber membrane and the hollow fiber membrane used according to the invention may be < 10 nm and the supporting structure can have pore diameters up to 10 pm.
Preferably, the content of polyvinylpyrrolidone in the inner or in the outer membrane surface layer is at least 10 % by weight, based on the total weight of the membrane. In a further embodiment, the content of polyvinylpyrrolidone in the inner and the outer membrane surface layer is at least 10 weight%, based on the total weight of the membrane.
Preferably, the PVP content in the inner membrane surface layer (SLjn) is at least 10% by weight, based on the total weight of the membrane. This content is also called PVPjn. More specifically, PVPin is at least 11 % by weight, even more specifically at least 12% by weight. In a further embodiment, PVPjn is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, PVPjn is at least
16% by weight. In particular, PVPjn may be 10 to 30% by weight, more specifically 10 to 20% by weight.
Preferably, the PVP content in the outer membrane surface layer (SL0Ut) is at least 10% by weight based on the total weight of the membrane. This content is also called PVP0Ut. More specifically, PVP0Ut is at least 11% by weight, even more specifically at least 12% by weight. In a further embodiment, PVP0Ut is at least 13% by weight, more specifically at least 14% by weight, even more specifically at least 15% by weight. In still a further embodiment, PVP0Ut is at least 16% by weight. In particular, PVP0Ut may be 10 to 30% by weight, more specifically 10 to 20% by weight.
The inventive hollow fiber membrane is characterized by exhibiting high water transfer rates while selectively withholding gas such as nitrogen. This combination of properties makes the inventive membranes particularly useful for the use in humidifies, in particular in fuel cell membrane humidifiers, where water vapor needs to selectively pass through the membrane. In particular, in fuel cell humidifier assemblies a gaseous exhaust composition is supplied to the fuel cell and undesired gas contained therein, such as, in particular nitrogen, needs to be withheld.
Further gasses that may be contained in the gaseous composition supplied to the fuel cell are, for example, nitrogen, oxygen, carbon dioxide, carbon monoxide, noble gasses and/or ambient air.
According to the invention, the hollow fiber membrane preferably has a water vapor transmission rate of at least 3.5 kg/h m2 at 80 °C, more specifically of at least 3.6 kg/h m2 at 80 °C, even more specifically of at least 3.7 kg/h m2 at 80 °C at a water flux (WET-IN) of 10 g/ s m2. In particular, the hollow fiber membrane preferably has a water vapor transmission rate of at least 3.8 kg/h m2 at 80 °C, more specifically of at least 3.9 kg/h m2 at 80 °C, even more specifically of at least 4.0 kg/h m2 at 80 °C at a water flux (WET-IN) of 10 g/ s m2.
According to the invention, the hollow fiber membrane preferably has a nitrogen gas permeability of 3 L/m2 h bar or lower at 2 bar, more specifically of 2.9 L/m2 h bar or lower at 2 bar, even more specifically of 2.8 L/m2 h bar or lower at 2 bar, measured before contact with water vapor. In particular, the hollow fiber membrane preferably has a nitrogen gas permeability of 2.7 L/m2 h bar or lower at 2 bar, more specifically of 2.6 L/m2 h bar or lower at 2 bar, even more specifically of 2.5 L/m2 h bar or lower at 2 bar, measured before contact with water vapor. According to a very specific embodiment, the hollow fiber membrane preferably has a nitrogen gas permeability of 2.4 L/m2 h bar or lower at 2 bar, more specifically of 2.3 L/m2 h bar or lower at 2 bar, even more specifically of 2.2 L/m2 h bar or lower at 2 bar, measured before contact with water vapor. According to a further very specific embodiment, the hollow fiber membrane preferably has a nitrogen gas permeability of 2.1 L/m2 h bar or lower at 2 bar, more specifically of
2.0 L/m2 h bar or lower at 2 bar, even more specifically of 1.9 L/m2 h bar or lower at 2 bar, measured before contact with water vapor.
According to the invention, the hollow fiber membrane preferably has a Brunauer-Emmet-Teller (BET) value of the surface (=overall surface of the membrane measured) of 35 m2/g or lower, in particular 34 m2/g or lower, more specifically 33 m2/g or lower. Even more particularly, the hollow fiber membrane preferably has BET value of the surface of 32 m2/g or lower, in particular 31 m2/g or lower, more specifically 30 m2/g or lower. It may be preferred, if the BET value of the surface is 29 m2/g or lower, in particular 28 m2/g or lower. The BET surface is determined by gas-adsorption-desorption (GAD) experiments with nitrogen by 5-point method with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The samples are activated at 130 °C for 15 min before measurement
A further aspect of the present invention is a method for the preparation of the inventive hollow fiber membrane, wherein the process comprises the steps: a) providing a solution (S) which comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80, and at least one solvent (D); b) passing the solution (S) through a spinneret and contacting the hollow fiber formed with at least one protic polar solvent, thereby forming the hollow fiber membrane; and c) isolating the hollow fiber membrane without carrying out a step of removal of the additive (A) from the membrane.
In step a), a solution (S) is provided comprising the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), as defined and preferably defined herein, a water-soluble polymer additive (A), and at least one solvent (D), wherein the water-soluble polymer additive (A) comprises polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80 as defined and preferably defined herein.
The solution (S) in step a) can be provided by any method known to the skilled person. For example, the solution (S) can be provided in step a) in customary vessels that may comprise a stirring device and preferably a temperature control device. Preferably, the solution (S) is provided by dissolving the polymer (P) and the water-soluble polymer additive (A) in the at least one solvent (D).
The dissolution of the polymer (P) and the water-soluble polymer additive (A) in the at least one solvent (D) to provide the solution (S) is preferably effected under agitation.
Step a) is preferably carried out at elevated temperatures, especially in the range from 20 to 100 °C, more preferably in the range from 40 to 80 °C. A person skilled in the art will choose the temperature in accordance with the at least one solvent (D).
The solution (S) preferably comprises the polymer (P) and the water-soluble polymer additive (A) completely dissolved in the at least one solvent (D). This means that the solution (S) preferably comprises no solid particles of the polymer (P) and the water-soluble polymer additive (A).
The at least one polymer (P) used in the inventive process is selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and is defined and preferably defined above.
The solution (S) may comprise from 1 to 50% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), in particular from 1 to 45% by weight, specifically from 5 to 40% by weight, more specifically from 8 to 35% by weight, based in each case on the total weight of the solution (S).
The water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80 is as defined and preferably defined above.
Preferably, the water-soluble polymer additive (A) comprises at least 50% by weight, preferably at least 60% by weight, in particular at least 70% by weight of PVP in relation to the total weight of additive (A) in the solution (A). In a preferred embodiment, the water-soluble polymer additive (A) consists of polyvinylpyrrolidone as defined and preferably defined above.
Preferably, the solution (S) comprises at least 3 % by weight, more specifically at least 4% by weight, even more specifically at least 4.5% by weight of the polyvinylpyrrolidone (PVP) with a solution viscosity characterized by a K-value of at least 80, based in each case on the total weight of the solution (S). In particular, the solution (S) may comprise 3 to 30% by weight, more specifically from 3 to 25% by weight, even more specifically from 3 to 20% by weight of the water-soluble polymer additive (A), based in each case on the total weight of the solution (S). According to a further embodiment, the solution (S) comprises at least 4 % by weight, more specifically 4 to 30% by weight, even more specifically 5 to 30% by weight of the polyvinylpyrrolidone (PVP) with a solution viscosity characterized by a K-value of at least 80, based in each case on the total weight of the solution (S).
As described above, the water-soluble polymer additive (A) used in the process of the inventive comprises polyvinylpyrrolidone, but may also additionally comprise other suitable water-soluble additives such as, for example selected from poly(alkylene oxides) and alcohols.
Examples for suitable poly(alkylene oxides) that may be comprised in the water-soluble polymer additive (A) are poly(ethylene oxide), polypropylene oxide) and poly(ethylene oxide)-
polypropylene oxide) copolymer. Examples for suitable alcohols that may be comprised in the water-soluble polymer additive (A) are divalent alcohols or trivalent alcohols like glycerol.
According to one embodiment, the water-soluble polymer additive (A) comprises 60 to 90% by weight of polyvinylpyrrolidone and from 10 to 40% by weight of at least one alcohol, preferably glycerol.
According to one embodiment, the solution (S) comprises from 1 to 50% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), from 3 to 30% by weight of the water-soluble polymer additive (A) consisting of PVP as defined and preferably defined herein, and from 20 to 96% by weight of the at least one solvent (D), based in each case on the total weight of the solution (S).
According to a further embodiment, the solution (S) comprises from 1 to 40% by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), from 3 to 20% by weight of the water-soluble polymer additive (A) consisting of PVP as defined and preferably defined herein, and from 40 to 96% by weight of the at least one solvent (D), based in each case on the total weight of the solution (S).
“At least one solvent” within the context of the present invention means precisely one solvent, and also a mixture of two or more solvents. The at least one solvent (D) can be any solvent known to the skilled person that is suitable for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and the water-soluble polymer additive (A). Preferably, the at least one solvent (D) is soluble in water.
Therefore, the at least one solvent (D) is preferably selected from the group consisting of N- alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2- pyrrolidone and N-tert.-butyl-2-pyrrolidone, 2-pyrrolidone, N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, N,N-dimethyl-2-hydroxypropan amide, N,N-diethyl-2-hydroxypropan amide, y-valerolactone, dihydrolevoglucosenone, methyl 5-(dimethylamino)-2-methyl-5- oxopentanoate and sulfolane. N-alkyl-2-pyrrolidone, y-valerolactone and N,N-dimethyl-2- hydroxypropan amide are particularly preferred. N-methylpyrrolidone is most preferred as the at least one solvent (D).
The solution (S) can comprise, for example, in the range from 20 to 96% by weight of the at least one solvent (D), preferably in the range from 40 to 96% by weight of the at least one solvent (D), more preferably in the range from 50 to 70% by weight of the at least one solvent (D), based on the total weight of the solution (S).
To the person skilled in the art it is clear that the percentages by weight of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sul-
fone), the water-soluble polymer additive (A) and the least one solvent (D). typically add up to 100 % by weight.
The duration of step a) may vary between wide limits and is preferably in the range from 10 min to 48 h (hours), especially in the range from 10 min to 24 h, and more preferably in the range from 15 min to 12 h. A person skilled in the art will choose the duration of step a) so as to obtain a homogeneous solution of the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and the water-soluble polymer additive (A) in the at least one solvent (D).
In step b), the solution (S) is passed through a spinneret and the hollow fiber formed is contacted with at least one protic polar solvent, thereby forming the hollow fiber membrane. For producing multi-bore hollow fibers step b) may be performed by extruding the solution (S) through an extrusion nozzle (also called spinneret) with the required number of hollow needles. In particular, the hollow fiber is preferably introduced into a liquid comprising at least one protic polar solvent.
Before carrying out step b), it is possible to filter solution (S) to obtain a filtered solution (S). Moreover, it is possible to degas the solution (S) before step b) is carried out. The degassing of the solution (S) can be carried out by any method known to the skilled person, for example, via vacuum or by allowing the solution (S) to rest.
Preferably, the single bore or multi-bore hollow fiber membrane is obtained by following a phase inversion process, which means that the composition of dissolved at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and water-soluble polymer additive (A) are transformed into a solid phase.
Phase inversion processes are in general known to the person skilled in the art.
The phase inversion process can, for example, be performed by cooling down the solution, wherein the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) comprised in the solution precipitates. Another possibility to perform the phase inversion process is to bring the solution in contact with a gaseous liquid that is a non-solvent for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone). The at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) will then as well precipitate.
Suitable gaseous liquids that are non-solvents for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) are, for example, protic polar solvents described hereinafter in their gaseous state. Another phase inversion process which is preferred within the context of the present invention is the phase inversion by immersing the solution into at least one protic polar solvent.
Therefore, according to step b) of the inventive process, the hollow fiber formed from the solution (S) is contacted with at least one protic solvent. This leads to the formation of the hollow fiber membrane.
In particular, according to one embodiment of step b), the hollow fiber is contacted with the at least one protic polar solvent by introducing the hollow fiber into a liquid comprising said at least one protic solvent. The liquid may be a bath, such as a coagulation bath.
Suitable at least one protic polar solvents are known to the skilled person. The at least one protic polar solvent is preferably a non-solvent for the at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone). Preferred at least one protic polar solvents are water, methanol, ethanol, n-propanol, iso-propanol, glycerol, ethylene glycol and mixtures thereof.
Preferably, the at least one protic polar solvent is a water-based coagulation liquid. Therefore, another object of the present invention is a method for the preparation of a hollow fiber membrane, wherein the at least one protic polar solvent in step c) is a water-based coagulation liquid.
The water-based coagulation liquid may comprise further components besides water, such as, for example, the same solvent (D) as comprised in the solution (S) or an alcohol, such as, for example, glycerol.
The at least one polar solvent used as coagulating liquid may also be injected through the hollow needles into the extruded polymer solution (S) during the step of passing the solution through the spinneret. Thereby, parallel continuous channels extending in extrusion direction are formed.
The contacting with the at least one protic solvent is preferably carried out at a temperature in the range of 20 to 80°C, more preferably at a temperature in the range of 20 to 60°C. In particular, the at least one protic polar solvent, in particular the water-based coagulation liquid, is held at a temperature in a range of 20 to 80°C, more preferably at a temperature in the range of 20 to 60°C.
In particular, according to a particular preferred embodiment, for the formation of the hollow fiber membrane according to step b), the coagulation liquid as defined above is injected through the hollow needles into the extruded polymer during extrusion. By this setup, the extruded polymer membrane gets a hollow cylindrical geometry and parallel continuous channels extending in extrusion direction are formed in the extruded polymer. Subsequently, the formed hollow fiber is preferably brought in contact with water as coagulation agent. The parameters of the process, like extrusion speed, temperature, nozzle geometry, type of coagulant, concentrations may have an effect on and thus can be used to control parameters such as the membrane’s shape
and thickness and thus the performance of the membrane. Hollow fiber membranes can be optionally wound up onto rolls and/or bundled to bundles of hollow fibers.
Subsequently, the hollow fiber membrane is isolated according to step c) without carrying out a step of removal of the additive (A) from the membrane.
In this connection, “without carrying out a step of removal of the additive (A) from the membrane” means, that the hollow fiber membrane formed in the inventive process is not subjected to a particular washing step aiming at the removal of the water-soluble polymer additive (A) from the membrane. In particular, no oxidative post-treatment with for example sodium hypochlorite or the like is being performed.
According to a preferred embodiment, the inventive process also comprises a step of d) rinsing with a liquid comprising water, preferably at elevated temperatures such as 60 °C.
Preferably the liquid consists of water.
Step d) may be desired and can be optionally carried out to remove residual components from the membrane such as residual amounts of solvent D). Under the conditions of the rinsing step using water, the additive (A), in particular the polyvinylpyrrolidone (PVP) with a K-value of at least 80 contained therein, is not washed out in a substantial extent.
According to a further preferred embodiment, the inventive process also comprises the step of e) drying the hollow fiber membrane.
Drying can be carried out by any means known to the person skilled in the art of membranes.
According to a further aspect, the present invention relates to a hollow fiber membrane obtainable by the inventive process as described herein.
The obtained inventive hollow fiber membrane is essentially free from the at least one solvent (D). “Essentially free” within the context of the present invention means that the membrane comprises at most 1 % by weight, preferably at most 0.5 % by weight and particularly preferably at most 0.1 % by weight of the at least one solvent based on the total weight of the hollow fiber membrane.
In a fuel cell humidifier, usually water vapor from the exhaust gas of the fuel cell reaction is used to be provided to the fuel cell membrane. The water vapor permeates through a membrane as selectively as possible to be provided to the polymeric electrolyte membrane.
It has been found with the present invention that the hollow fiber membranes described herein, in particular the membranes according to the present invention, can successfully be used as membrane in a humidifier in a fuel cell, because water vapor can pass through the humidifier membrane while gas contained in the gaseous mixture is withheld. In particular, the hollow fiber
membranes have proven to be selectively gas-tight with respect to unwanted gas, such as for example nitrogen and that the membranes are effective at the operation temperatures of a fuel cell which is usually at 80 to 90 °C. The hollow fiber membranes described herein have shown to perform particularly well and selectively in this temperature range.
According to a further aspect, the present invention thus relates to a separation element, a membrane module, a membrane cartridge or a separation system comprising the inventive hollow fiber membrane as described herein.
Still a further object of the present invention is a humidifier comprising the inventive hollow fiber membrane as described herein, in particular a humidifier which is a fuel cell membrane humidifier.
Still a further object of the present invention is a humidifier comprising a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), and wherein the membrane comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP). In particular, the humidifier is a fuel cell membrane humidifier.
In still a further aspect, the present invention relates to a fuel cell comprising a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), and wherein the membrane comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP).
In still a further aspect, the present invention relates to a fuel cell comprising the inventive hollow membrane as described herein.
In still a further aspect, the present invention relates to a fuel cell comprising a separation element, membrane module, membrane cartridge or separation system comprising the inventive hollow fiber membrane as described herein.
In still a further aspect, the present invention relates to a fuel cell comprising a humidifier, in particular a fuel cell membrane humidifier, wherein said humidifier comprises a hollow fiber membrane, wherein the membrane comprises a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), and wherein the membrane comprises at least one poly(arylene ether sulfone) polymer (P) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP).
In still a further aspect, the present invention relates to a fuel cell comprising an inventive humidifier, in particular a fuel cell membrane humidifier as described herein.
Examples
Abbreviations and compounds used in the examples:
NTU nephelometric turbidity unit
WTR water transmission rate
NMP N-methyl-2-pyrrolidone [CAS 872-50-4]
PVP Polyvinylpyrrolidone
BET Brunauer-Emmet-Teller surface assessment
PAES Poly(arylene ether sulfone) used in the examples:
Ultrason® E 6020 P: Polyethersulfone with a viscosity number (measured based on ISO 1628-5 (1998) in a 1wt.-% polymer solution in N- methylpyrrolidone) of 81 ml/g; a glass transition temperature (DSC, 10 K/min; according to ISO 11357-1 (2017) and 11357-2 (2020)) of 225 °C; a molecular weight Mw (GPC in THF, PS standard) of 75000 g/mol, and Mw/Mn = 3.4
Luvitec® K90 Polyvinylpyrrolidone with a solution viscosity characterized by the K- value of 90, determined according to the method of Fikentscher (Fikentscher, Cellulosechemie 13, 1932 (58))
Turbidity
The polymer solution turbidity was measured with a turbidimeter 2100AN (Hach Lange GmbH, Dusseldorf, Germany) employing a filter of 860 nm at 60 °C and expressed in nephelometric turbidity units (NTU). NTU values below 1 are preferred.
WTR rate, nitrogen permeability
The water vapor transmission rate (WTR, g/s m2) was tested on mini modules comprising 8 to 10 hollow fibers of 10 cm length. Also, the nitrogen permeability (L/m2 h bar) at a pressure of 2 bar was assessed before and after WTR measurements at 80 and 90 °C. A high WTR in combination with low nitrogen leakage is desired.
Viscosity
The polymer solution viscosity was measured with a Brookfield Viscometer DV-I Prime (Brookfield Engineering Laboratories, Inc. Middleboro, USA) with RV 6 spindle at 60 °C with 20 rpm.
PVP content
The polyvinylpyrrolidone (PVP) content of the membranes (PVPtotai) was determined by dissolving the membrane sample in N,N-dimethylformamide (DMF) and casting the solution as film on KRS-5 windows of thalliumbromiodide. The films were dried at 160 °C and analyzed with a Ni- colet 6700 FT-IR spectrometer (Thermo Fischer Scientific, Waltham, Massachusetts, USA). Together with calibration samples of known polyvinylpyrrolidone content, the adsorption band at 1680 cm-1 was used to determine the overall polyvinylpyrrolidone content of the membrane samples. The polyvinylpyrrolidone content of the inner membrane surface layer and outer membrane surface layer (PVPjn, PVP0Ut) was estimated with the same adsorption band by attenuated infrared spectroscopy (ATR) and reference samples.
BET surface assessment
Solvent exchanged and dried membrane samples were used for Brunauer-Emmet-Teller (BET) surface assessment. The wet membrane samples were stored for 12 h subsequently in wa- ter/ethanol (1 :1 wt/wt), water/ethanol (1 :2 wt/wt), ethanol/n-hexane (1 :1 wt/wt) and finally n- hexane before drying at 60 °C under vacuum. The BET surface was determined by gas- adsorption-desorption (GAD) experiments with nitrogen by 5-point method with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The samples were activated at 130 °C for 15 min before measurement.
Preparation of hollow fiber membranes
General procedure
The amounts given in this general procedure are general ranges, the exact amount for the respective experiment can be found in table 1 . A clear viscous solution containing 19 wt% membrane polymer and 5 wt% polyvinylpyrrolidone in 76 wt% NMP was prepared using a Speed- Mixer® DAC 600.1 Vac-P (Hauschild & Co. KG, Hamm, Germany) at speeds of 200, 800 and 1200 rpm within 30 minutes of mixing. The solution was degassed overnight at room temperature. A center fluid was prepared by mixing distilled water and N-Methylpyrrolidone (NMP). The weight fraction of the two components in the center fluid was: water : NMP = 60 wt %: 40 wt %.
A hollow fiber membrane was formed by reheating the polymer solution at 60°C for 2 hours and passing the solution as well as the center fluid through a spinning die. The diameter of the spinning die was 0.33 mm - 0.62 mm - 1.3 mm. The temperature of the die was 60° C. The hollow fiber was formed at a spinning speed of 13 cm/min. The polymer solution leaving the die with 3.0 ml/min while the center fluid was leaving the die with 3.3 ml/min. The liquid capillary was passed into a water bath having a temperature of 24° C. The distance between the die and the precipitation bath was 13 cm. The hollow fiber membrane formed was guided through one water bath and subsequently was wound onto a winding reel. Afterwards the membrane was directly
dried (treatment A) or treated with 2000 ppm aqueous sodiumhypochlorite (NaOCI) at pH 9.5 for 3 hours and 20 hours water extraction at 80 °C with subsequent drying (post treatment B).
Table 1 : Composition and properties of humidifier membranes prepared from a blend of PAES and PVP (PVP K90).
Table 2: Properties of humidifier membranes prepared from a blend of PAES and PVP (PVP K90); with treatment A or B (=post treatment); PVP contents according to infrared (IR) analysis and fiber dimensions according to scanning electron microscopy (SEM).
Table 3: Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); nitrogen permeability at 2 bar pressure.
Table 4: Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); water transmission rate (WTR, kg/ h m2) at 80 °C at a given water flux (WET-IN, g/ s m2).
Table 5: Properties of humidifier membranes prepared from a blend of PAES and PVP (K90); water transmission rate (WTR, kg/ h m2) at 90 °C at a given water flux (WET-IN, g/ s m2).
The hollow fiber membranes according to the invention show a particularly low gas leakage of < 10 L/m2 h bar (table 3), and, at the same time, have high water transmission rates (WTR rates) at temperatures of 80 and 90 °C at all relevant water flux values (tables 4 and 5). In contrast, the post treated open porous hollow fiber M-2B shows higher WTR rates but significantly higher nitrogen leakage, which makes it useless for fuel cell membrane humidifiers.
Figure 1 Secondary electron microscopy of M-2A (150 x and 1500 x magnification).
Claims
1 . A use of a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a fuel cell membrane humidifier.
2. A use of a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
3. A hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising at least 10 % by weight, based on the total weight of the membrane, polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80.
4. The membrane of claim 3, wherein the content of the polyvinylpyrrolidone in the inner and/or outer membrane surface layer is at least 10 % by weight based on the total weight of the membrane.
5. The membrane of claim 3 or 4, wherein at least one of the inner and outer membrane surface layer has a water vapor transmission rate of at least 3.5 kg/h m2 at 80 °C at a water flux of 10 g/ s m2.
6. The membrane of any one of claims 3 to 5, wherein at least one of the inner and outer membrane surface layer has a nitrogen gas permeability of 3 L/m2 h bar or lower at 2 bar.
7. The membrane of any one of claims 3 to 6, wherein the BET (Brunauer-Emmet-Teller) value of the hollow fiber membrane is 30 m2/g or less.
8. The membrane of any one of claims 3 to 7, wherein the at least one polymer (P) does not contain any sulfonated poly(arylene ether sulfone).
9. A method for the preparation of a hollow fiber membrane according to any one of claims 3 to 8 comprising the steps: a) providing a solution (S) which comprises at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), a water-
soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K-value of at least 80, and at least one solvent (D); b) passing the solution (S) through a spinneret and contacting the hollow fiber formed with at least one protic polar solvent, thereby forming the hollow fiber membrane; and c) isolating the hollow fiber membrane without carrying out a step of removal of the additive (A) from the membrane.
10. The process of claim 9, wherein the solution (S) comprises at least 3 % by weight of the polyvinylpyrrolidone (PVP) with a solution viscosity characterized by a K-value of at least 80.
11. A hollow fiber membrane obtainable by the process of claim 9 or 10.
12. A separation element, a membrane module, a membrane cartridge or a separation system comprising the hollow fiber membrane according to any one of claims 3 to 8 or 11 .
13. A humidifier comprising a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), or the hollow fiber membrane according to any one of claims 3 to 8 or 11 .
14. The humidifier of claim 13, which is a fuel cell membrane humidifier.
15. A fuel cell comprising a hollow fiber membrane comprising a porous supporting structure, an inner membrane surface layer (SLjn) and an outer membrane surface layer (SL0Ut), the membrane comprising at least one polymer (P) selected from a sulfonated poly(arylene ether sulfone) and a poly(arylene ether sulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), the hollow fiber membrane according to any one of claims 3 to 8 or 11 , the separation element, membrane module, membrane cartridge or separation system according to claim 12 or the humidifier according to claim 13 or 14.
16. A use of a hollow fiber membrane according to any one of claims 3 to 8 or 11 in a fuel cell membrane humidifier.
17. A use of a hollow fiber membrane according to any one of claims 3 to 8 or 11 for selectively withholding nitrogen gas and selectively letting through water vapor from a gaseous mixture comprising water vapor and nitrogen.
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| EP23169205.4 | 2023-04-21 |
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| US20210154624A1 (en) | 2018-06-12 | 2021-05-27 | Kolon Industries, Inc. | Composite hollow fiber membrane, manufacturing method therefor, hollow fiber membrane cartridge including same, and fuel cell membrane humidifier |
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