USRE34058E - Multilayer reverse osmosis membrane of polyamide-urea - Google Patents
Multilayer reverse osmosis membrane of polyamide-urea Download PDFInfo
- Publication number
- USRE34058E USRE34058E US07/784,245 US78424591A USRE34058E US RE34058 E USRE34058 E US RE34058E US 78424591 A US78424591 A US 78424591A US RE34058 E USRE34058 E US RE34058E
- Authority
- US
- United States
- Prior art keywords
- membrane
- iaddend
- iadd
- substrate
- polyamide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 108
- 238000001223 reverse osmosis Methods 0.000 title claims abstract description 12
- 239000004202 carbamide Substances 0.000 title claims 6
- 239000000758 substrate Substances 0.000 claims abstract description 50
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical class NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 claims description 24
- 229920002492 poly(sulfone) Polymers 0.000 claims description 22
- 150000003839 salts Chemical class 0.000 claims description 17
- -1 monoisocyanato isophthaloyl halide Chemical class 0.000 claims description 15
- 230000004907 flux Effects 0.000 claims description 10
- 239000004952 Polyamide Substances 0.000 claims description 7
- 229920002647 polyamide Polymers 0.000 claims description 7
- 125000003118 aryl group Chemical class 0.000 claims description 6
- 239000012510 hollow fiber Substances 0.000 claims description 6
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical class NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 claims description 5
- 125000000962 organic group Chemical group 0.000 claims description 5
- 150000004984 aromatic diamines Chemical class 0.000 claims description 4
- 229920000728 polyester Polymers 0.000 claims description 4
- 150000001266 acyl halides Chemical class 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 150000004820 halides Chemical class 0.000 claims description 2
- 239000005373 porous glass Substances 0.000 claims description 2
- 239000007795 chemical reaction product Substances 0.000 claims 5
- 150000001555 benzenes Chemical class 0.000 claims 2
- 229920000098 polyolefin Polymers 0.000 claims 1
- 150000004985 diamines Chemical class 0.000 abstract description 14
- 150000001263 acyl chlorides Chemical class 0.000 abstract description 7
- 238000006243 chemical reaction Methods 0.000 abstract description 7
- 238000011065 in-situ storage Methods 0.000 abstract description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 52
- QYAMZFPPWQRILI-UHFFFAOYSA-N 5-isocyanatobenzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC(N=C=O)=CC(C(Cl)=O)=C1 QYAMZFPPWQRILI-UHFFFAOYSA-N 0.000 description 40
- 239000011780 sodium chloride Substances 0.000 description 27
- 229940018564 m-phenylenediamine Drugs 0.000 description 26
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 21
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 19
- 239000000243 solution Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 17
- 239000002904 solvent Substances 0.000 description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 14
- 230000035699 permeability Effects 0.000 description 14
- 239000000203 mixture Substances 0.000 description 12
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 10
- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 description 9
- 239000012466 permeate Substances 0.000 description 8
- 239000000377 silicon dioxide Substances 0.000 description 7
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 description 6
- 238000005266 casting Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000010612 desalination reaction Methods 0.000 description 4
- 239000012527 feed solution Substances 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 239000012948 isocyanate Substances 0.000 description 4
- 150000002513 isocyanates Chemical class 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- KBZFDRWPMZESDI-UHFFFAOYSA-N 5-aminobenzene-1,3-dicarboxylic acid Chemical compound NC1=CC(C(O)=O)=CC(C(O)=O)=C1 KBZFDRWPMZESDI-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 238000012695 Interfacial polymerization Methods 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical class ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 3
- 239000004695 Polyether sulfone Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- FDLQZKYLHJJBHD-UHFFFAOYSA-N [3-(aminomethyl)phenyl]methanamine Chemical compound NCC1=CC=CC(CN)=C1 FDLQZKYLHJJBHD-UHFFFAOYSA-N 0.000 description 3
- 125000001931 aliphatic group Chemical group 0.000 description 3
- 150000001412 amines Chemical class 0.000 description 3
- 150000004982 aromatic amines Chemical class 0.000 description 3
- 239000003054 catalyst Chemical class 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 238000002481 ethanol extraction Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 229920006393 polyether sulfone Polymers 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- AJDIZQLSFPQPEY-UHFFFAOYSA-N 1,1,2-Trichlorotrifluoroethane Chemical compound FC(F)(Cl)C(F)(Cl)Cl AJDIZQLSFPQPEY-UHFFFAOYSA-N 0.000 description 2
- JFEYGNBXTUDJAM-UHFFFAOYSA-N 3,5-diisocyanatobenzoyl chloride Chemical compound ClC(=O)C1=CC(N=C=O)=CC(N=C=O)=C1 JFEYGNBXTUDJAM-UHFFFAOYSA-N 0.000 description 2
- PICVAYJGENMBAJ-UHFFFAOYSA-N 4-isocyanatobenzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=C(N=C=O)C(C(Cl)=O)=C1 PICVAYJGENMBAJ-UHFFFAOYSA-N 0.000 description 2
- OTEBFHVUSAGHHW-UHFFFAOYSA-N 5-isocyanatobenzene-1,3-dicarbonyl bromide Chemical compound BrC(=O)C1=CC(N=C=O)=CC(C(Br)=O)=C1 OTEBFHVUSAGHHW-UHFFFAOYSA-N 0.000 description 2
- XVWVQASFSJJMBI-UHFFFAOYSA-N 5-isocyanatocyclohexane-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1CC(N=C=O)CC(C(Cl)=O)C1 XVWVQASFSJJMBI-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 2
- 229920002396 Polyurea Polymers 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- HIZMBMVNMBMUEE-UHFFFAOYSA-N cyclohexane-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1CC(C(Cl)=O)CC(C(Cl)=O)C1 HIZMBMVNMBMUEE-UHFFFAOYSA-N 0.000 description 2
- 235000013365 dairy product Nutrition 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- 230000003204 osmotic effect Effects 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000008213 purified water Substances 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- PQDIQKXGPYOGDI-UHFFFAOYSA-N 1,3,5-triisocyanatobenzene Chemical compound O=C=NC1=CC(N=C=O)=CC(N=C=O)=C1 PQDIQKXGPYOGDI-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- RSAXKGPIPWRPKR-UHFFFAOYSA-N 2-isocyanatobenzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1N=C=O RSAXKGPIPWRPKR-UHFFFAOYSA-N 0.000 description 1
- COOYZPDFMWOFKV-UHFFFAOYSA-N 2-isocyanatobenzene-1,4-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=C(C(Cl)=O)C(N=C=O)=C1 COOYZPDFMWOFKV-UHFFFAOYSA-N 0.000 description 1
- NCNXDAMIPYEADP-UHFFFAOYSA-N 5-aminobenzene-1,3-dicarboxylic acid;hydrochloride Chemical compound Cl.NC1=CC(C(O)=O)=CC(C(O)=O)=C1 NCNXDAMIPYEADP-UHFFFAOYSA-N 0.000 description 1
- 239000004801 Chlorinated PVC Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 101100386054 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) CYS3 gene Proteins 0.000 description 1
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 description 1
- JAWMENYCRQKKJY-UHFFFAOYSA-N [3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-ylmethyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl]-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]methanone Chemical compound N1N=NC=2CN(CCC=21)CC1=NOC2(C1)CCN(CC2)C(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F JAWMENYCRQKKJY-UHFFFAOYSA-N 0.000 description 1
- 125000000777 acyl halide group Chemical group 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- UWCPYKQBIPYOLX-UHFFFAOYSA-N benzene-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1=CC(C(Cl)=O)=CC(C(Cl)=O)=C1 UWCPYKQBIPYOLX-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 229920000457 chlorinated polyvinyl chloride Polymers 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 150000001924 cycloalkanes Chemical class 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 125000005442 diisocyanate group Chemical group 0.000 description 1
- IUEVXLACZFKZSP-UHFFFAOYSA-L disodium;5-aminobenzene-1,3-dicarboxylate Chemical compound [Na+].[Na+].NC1=CC(C([O-])=O)=CC(C([O-])=O)=C1 IUEVXLACZFKZSP-UHFFFAOYSA-L 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 235000015203 fruit juice Nutrition 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000010406 interfacial reaction Methods 0.000 description 1
- 125000001261 isocyanato group Chemical group *N=C=O 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000008267 milk Substances 0.000 description 1
- 235000013336 milk Nutrition 0.000 description 1
- 210000004080 milk Anatomy 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 229920000768 polyamine Polymers 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 150000003141 primary amines Chemical class 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000019333 sodium laurylsulphate Nutrition 0.000 description 1
- PHIQPXBZDGYJOG-UHFFFAOYSA-N sodium silicate nonahydrate Chemical compound O.O.O.O.O.O.O.O.O.[Na+].[Na+].[O-][Si]([O-])=O PHIQPXBZDGYJOG-UHFFFAOYSA-N 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 101150035983 str1 gene Proteins 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
Classifications
-
- 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
- B01D71/56—Polyamides, e.g. polyester-amides
-
- 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
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/125—In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
- B01D69/1251—In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction by interfacial polymerisation
-
- 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
- B01D71/54—Polyureas; Polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3225—Polyamines
- C08G18/3237—Polyamines aromatic
- C08G18/324—Polyamines aromatic containing only one aromatic ring
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3225—Polyamines
- C08G18/3246—Polyamines heterocyclic, the heteroatom being oxygen or nitrogen in the form of an amino group
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/71—Monoisocyanates or monoisothiocyanates
- C08G18/712—Monoisocyanates or monoisothiocyanates containing halogens
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
- C08G18/773—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur halogens
Definitions
- the present invention relates to composite membranes suitable for use in reverse osmosis processes such as the desalination of aqueous solutions. More particularly, the present invention relates to a multilayer membrane in which one layer is a copolymer of polyamideurea.
- Reverse osmosis is a well-known process for purification of saline water.
- a pressure in excess of the osmotic pressure of the saline water feed solution is applied to the feed solution to separate purified water by use of a semipermeable premselective membrane. Purified water is thereby caused to diffuse through the membrane while salt and other impurities are retained by the membrane.
- Permselective membranes include composite membranes that include a separating layer on a supporting microporous substrate. The substrate is typically supported on a support fabric to impart mechanical strength to the membrane. Permselective membranes suitable for use in reverse osmosis are available in various forms and configurations. Flat sheet, tubular and hollow fiber membranes are well-known in the art. These membranes can also vary in morphology. Homogenous and asymmetric membranes are operable, as well as thin film composites.
- Permselective membranes are available in the form of multilayer structures that include a separating layer superimposed on a microporous polysulfone substrate layer.
- Membrane separating layers which may be employed include polyamides, polyphenylene esters, and polysulfonamides.
- Polyamide discriminating layers are well-known in the art.
- the polyamide can be aliphatic or aromatic and may be crosslinked.
- Polyamide membranes may be made by the interfacial reaction of a cycloaliphatic diamine with isophthaloyl chloride, trimesoyl chloride or mixtures of these acid chlorides.
- Polyamide membranes also may be made by reaction of m-phenylenediamine and cyclohexane-1,3,5-tricarbonyl chloride.
- the polyamide discriminating layer also may be made by reaction of aromatic polyamines having at least two primary amines on an aromatic nucleus and aromatic polyfunctional acyl halides having an average of more than two acyl halide groups on an aromatic nucleus.
- the present invention is directed to an improved reverse osmosis membrane that shows surprisingly increased solute rejection and permeation properties.
- the membrane includes a separating layer of a polyamideurea formed in situ on a microporous support by reaction of an isocyanate-substituted acyl chloride with a diamine.
- improved reverse osmosis membranes are made by treating a microporous polymeric substrate with aqueous polyfunctional amine to provide an impregnated substrate.
- the substrate then is treated with a solution of isocyanate-substituted isophthaloyl chloride in a solvent that is non-reactive with the substrate to provide a membrane of polyamideurea in contact with the substrate.
- the resulting membrane's surprisingly improved solute rejection and permeation properties enable the membrane to be employed in a wide variety of applications where high purity permeate is required.
- these applications include, but are not limited to, desalination of salt water, semiconductor manufacturing, reduction of BOD in waste water treatment, removal of dissolved salts during metal recovery, dairy processing such as milk processing, fruit juice concentration, and de-alcoholization of wine, beer, and the like.
- the liquid is placed under pressure while in contact with the improved membranes of the invention to remove impurities.
- the manufacture of the improved reverse osmosis membranes of the invention is accomplished by treating a microporous polymeric substrate with a solution of an aqueous polyfunctional amine, preferably a polyfunctional aromatic amine, and further treating the substrate with a solution of an isocyanate-substituted acyl chloride, such as 2-isocyanatoisophthaloyl chloride, 4-isocyanatoisophthaloyl chloride, 5-isocyanatoisophthaloyl chloride, 2-isocyanatoterephthaloyl chloride, 3,5-diisocyanatobenzyoyl chloride, 5-isocyanatocyclohexane-1,3-dicarbonyl chloride and 5-isocyanatoisophthaloyl bromide, preferably, 5-isocyanatoisophthaloyl chloride.
- the reaction of the isocyanate-substituted acyl chloride with the polyfunctional aromatic amine provides a novel composition of a
- isocyanate-substituted isophthaloyl chlorides may be prepared by reacting an amino-substituted isophthalic acid, or salts of amino-substituted isophthalic acid, catalyst, phosgene, and halogenated aliphatic solvent under elevated pressure and temperature.
- the 5-isocyanatoisophthaloyl chloride (ICIC) that is most preferably reacted with the diamine treated substrate is prepared by heating a mixture of 10 grams of 5-aminoisophthalic acid, a catalyst of 0.5 grams of imidazole, 60 grams of phosgene, and 50 ml of chlorobenzene solvent in a pressure vessel at 160° C. for 18 hours at under autogenous pressure. Removal of the solvent, followed by distillation of the product at 123°-128° C. and 0.2 mm Hg yields 8.8 grams of ICIC.
- ICIC also may be produced by using alternatives to the preferred reactants mentioned above.
- salts of 5-aminoisophthalic acid such as disodium 5-aminoisophthalate or 5-aminoisophthalic acid hydrochloride may be substituted for 5-aminoisophthalic acid.
- imidazole may be replaced with other heteroatom-containing compounds capable of complexing phosgene.
- catalysts include, but are not limited to pyridine, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and the like.
- solvents such as dioxane or methylene chloride may be employed, so long as the solvent is reasonably unreactive with the reactants and products.
- ICIC is most preferred as the isocyanato-substituted isophthaloyl chloride for reacting with the diamine-treated substrate to effect interfacial polymerization of polyamideurea.
- analogs such as 5-isocyanatoisophthaloyl bromide may be substituted for ICIC.
- homologs such as 3,5-diisocyanatobenzoyl chloride and positional isomers of ICIC such as 4-isocyanatoisophthaloyl chloride may be substituted for ICIC.
- Aliphatic analogs, such as 5-isocyanatocyclohexane-1,3-dicarbonyl chloride may be employed as well.
- isocyanate-substituted isophthaloyl chloride may be employed in combination with a difunctional isocyanate to effect polymerization with a diamine to yield polyamideurea; 2,4-toluenediisocyanate is one example of such a diisocyanate.
- the isocyanate-substituted isophthaloyl chloride also may be employed in combination with a diacyl chloride to effect polymerization with a diamine to provide polyamideurea. Isophthaloyl chloride is an example of such a diacyl chloride.
- the membranes of the present invention can be manufactured by first casting a suitable substrate for the membrane onto a support member.
- suitable substrate layers have been described extensively in the art.
- Illustrative substrate materials include organic polymeric materials such as polysulfone, polyethersulfone, chlorinated polyvinyl chloride, styrene/acrylonitrile copolymer, polybutylene terephthalate, cellulose esters and other polymers which can be prepared with a high degree of porosity and controlled pore size distribution. These materials are generally cast onto a support of non-woven fabric or woven cloth, generally of polyester or polypropylene.
- polysulfone is employed as the substrate.
- Porous inorganic materials also may be employed as the support material. Examples of such support compositions include porous glass, ceramics, sintered metals, and the like. These supports may be in the form of flat sheets, hollow tubes, hollow fibers, and the like to provide, for example, hollow fiber membranes.
- Preparation of microporous polysulfone substrate films is well known in the art. Preparation includes casting a 15-20% solution of polysulfone in dimethylformamide (DMF) onto a glass plate, followed immediately by immersing the cast polysulfone into water to produce the polysulfone film.
- the side of the polysulfone film exposed to air during casting is called the "face” and contains very small pores, mostly under 200 angstroms in diameter.
- the "back" of the film in contact with the glass plate has very coarse pores.
- the porous polysulfone substrate is treated with an aqueous solution of a polyfunctional diamine.
- Aqueous m-phenylenediamine (MPD) is preferred for treating the substrate.
- MPD m-phenylenediamine
- other diamines with sufficient water solubility to effect interfacial polymerization with isocyanato-substituted phthaloyl chlorides also may be employed.
- diamines include, but are not limited to, p-phenylenediamine, piperazine, m-xylylenediamine, and the like.
- the microporous polysulfone substrate is exposed to an aqueous solution of m-phenylenediamine (MPD) of indicated weight/volume (w/v) percent concentration at a temperature of 20° C. for 5 minutes.
- MPD m-phenylenediamine
- w/v weight/volume percent concentration
- the MPD-treated polysulfone substrate then is dipped into a solution of ICIC in a water-immiscible solvent under conditions suitable for effecting interfacial polymerization of polyamideurea of the general formula: ##STR1## where
- Y a divalent organic group.
- Suitable solvents are solvents which do not deleteriously affect the substrate.
- solvents include, but are not limited to C 5 -C 8 n-alkanes, C 5 -C 8 fluoroalkanes, C 2 -C 8 chlorofluoroalkanes, C 6 -C 8 cyclo alkanes, C 4 -C 8 cyclo fluoroalkanes, and C 4 -C 8 cyclo chlorofluoro alkanes.
- Freon TF (1,1,2-trichlorotrifluoroethane) is the preferred solvent for use in the ICIC solution.
- the concentration of the ICIC in the solution may vary depending on the specific solvent, substrate, and the like, and can be determined experimentally. Generally, concentrations of 0.03 to 5.0%, preferably 0.05 to 0.15 percent, can be employed.
- the resulting membrane is removed from the ICIC solution and drip dried for 3 to 120 seconds, preferably 60 to 120 seconds, most preferably for 120 seconds.
- the membrane then is treated to extract impurities such as residual diamines, reaction by-products, residual ICIC, and the like. This is accomplished by exposing the membrane to water and then to aqueous lower alkanols. Water extraction is accomplished with running tap water at 20° to 60° C., preferably 40° to 60° C., most preferably 40°-45° C. for 1 to 20 minutes, preferably 5 to 10 minutes, most preferably 10 minutes.
- the aqueous lower alkanols are preferably C 1 -C 3 alkanols such as methanol, ethanol, isopropanol, and the like.
- the aqueous ethanol employed may be 5 to 25 percent ethanol, preferably 10 to 15 percent ethanol, most preferably 15 percent ethanol, the remainder being water.
- the aqueous ethanol is at 20° to 60° C., preferably 40° to 50° C., most preferably 50° C.
- the exposure time of the membrane to aqueous ethanol is 1 to 20 minutes, preferably 5 to 10 minutes, most preferably 10 minutes.
- the membrane then is rinsed with water to remove residual ethanol and is stored in deionized water until testing.
- the membrane may be impregnated with a wetting agent such as glycerine to provide for dry storage and subsequent rewetting.
- the resulting membranes of polyamideurea on a polysulfone substrate are evaluated for salt rejection and flux by subjecting the membranes to a feed of aqueous 0.26%-0.28% NaCl at pH 6.8 and 25°-30° C. in a cross flow permeation cell.
- Membranes measuring 47 mm diameter are placed into the cell and exposed to 0.75 liters/minute of aqueous NaCl solution.
- the membranes are exposed to feed pressure of 420 psig for at least 14 hours, after which the feed pressure is lowered to 225 psig and the permeation properties determined.
- the performance of the membrane is characterized in terms of the percent of salt NaCl rejected (R), permeability (Kw), and permeate productivity.
- the percent salt rejected (R) is defined as
- C p and C f are the concentrations of NaCl in the permeate and feed, respectively.
- concentrations of the NaCl in the permeate and feed can be determined conductimetrically with a Beckman Gl conductivity cell (cell constant 1.0) and a YSI Model 34 conductivity meter.
- the permeability (Kw) is defined as (flux/effective pressure), where flux is the flow rate of water through the membrane, and the effective pressure is equal to the feed pressure minus the opposing osmotic pressure.
- Flux is expressed in terms of permeate productivity, that is, in terms of gallons of permeate/square foot membrane area/day (gfd) at 225 psig and 25° C.
- Permeability is expressed in terms of meters/second/teraPascal (m/s/Pa ⁇ 10 -12 ). Conversion, expressed as volume of permeate per unit time divided by volume of feed per unit time is typically below 2%.
- the membranes of the invention can be readily tailored to a specific application such as salt removal from drinking water, dairy processing, and the like by varying, for example, the concentration of the isocyanate substituted acyl halide employed to treat the diamine treated substrate. Accordingly, polyamideurea layers may be formed that are suitable for achieving salt rejections below 90 percent to more than 99 percent.
- the membranes can be employed in a variety of devices known in the prior art.
- flat sheets of the membrane can be utilized in either plate and frame, or spiral devices.
- Tubular and hollow fiber membranes can be assembled in generally parallel bundles in devices with tubesheets at opposing ends of the membranes. Radial, axial or down the bore flow feed can be utilized in hollow fiber devices.
- a microporous polysulfone substrate is prepared by knife casting a 16% solution of UDEL P3500 polyethersulfone, supplied by Union Carbide Corp. in N,N-dimethylformamide (DMF) containing 0.3% water onto a support of polyester sailcloth. The solution is cast at a knife clearance of 5.5 mil. The sailcloth bearing the cast polyethersulfone solution is immersed in a water bath within two seconds of casting to produce a microporous polysulfone substrate. The substrate is washed in water to remove the N,N-dimethylformamide and is stored damp until use.
- DMF N,N-dimethylformamide
- microporous polysulfone substrate is immersed in an aqueous solution of MPD for five minutes.
- the substrate is drained briefly and then excess MPD droplets are removed by rolling the face of the substrate with a soft rubber roller.
- the damp MPD-impregnated substrate then is immersed in a solution of 5-isocyanatoisophthaloyl chloride in FREON TF solvent for 40 seconds to form a membrane of polyamideurea.
- the membrane is removed from the ICIC solution and drip dried for 2 minutes.
- the membrane then is successively treated in 45° C., running tap water for ten minutes, and then in stirred 15% aqueous ethanol at 50° C. for 10 minutes.
- the membrane is stored in water containing 0.1% sodium bicarbonate until testing for permeability and flux.
- Examples 9-12 describe the use of n-hexane as the solvent for ICIC instead of FREON TF; all other conditions are identical to Examples 1-8. The results are reported in Table 2.
- Examples 13-14 show the utility of the membranes of the invention for removing dissolved silica from the feed solution.
- the amount of rejection of dissolved silica is determined for the membranes of Examples 3 and 6 by adding 170 ppm of sodium metasilicate nonahydrate to the 0.27% NaCl feed to give 36 ppm dissolved silica.
- Silica rejection is determined at 225 psig as described above for NaCl rejection.
- Silica concentration in the feed and permeate is determined by Method B of ASTM D 859. The results are given in Table 3.
- Example 17 illustrates the surprising effectiveness of the membranes of the invention for desalination of seawater.
- Example 17 the suitability of the membrane of Example 3 for seawater desalination is determined by changing the feed to 3.8% NaCl, pH 7 at 800 psig. The result is shown in Table 5.
- Examples 18-20 show treatment of a polysulfone substrate with other aromatic amines that can serve to interfacially react with ICIC to produce the membranes of the invention.
- Table 6 describes membranes treated with p-phenylenediamine (PPD) that are contacted with ICIC.
- PPD p-phenylenediamine
- the membranes are made under the conditions employed in Examples 1-8 except that PPD is substituted for MPD. The performance of these membranes is given in Table 6.
- Table 7 describes membranes formed by treating an MPD-impregnated substrate made with 1:1 mixture of ICIC and 1,3,5-cyclohexanetricarbonyl chloride (CHTC) under the general conditions of Examples 1-8. The performance of the resulting membranes is given in Table 7.
- Table 8 describes the performance of membranes made by treating an MPD impregnated polysulfone substrate with a 1:1 (wt) mixture of ICIC and isophthaloyl chloride (IC) under the conditions of Examples 1-8.
- the molar ratio of (ICIC:IC) in the mixture is 1:1.2, and the average functionally of the mixture is 2.45.
- the performance of the resulting membrane are shown in Table 8.
- Examples 27 and 28 show the use of other aromatic diamines for treating the polysulfone substrate to provide a substrate that can be interfacially reacted with ICIC to make the polyamideurea membranes of the invention.
- piperazine and m-xylylenediamine are each substituted for MPD, respectively.
- ICIC is then reacted with the resulting substrate under the conditions of Examples 1-8.
- the diamines employed to treat the polysulfone substrate contain 1% triethylamine as an acid acceptor and 0.5% sodium lauryl sulfate as a surfactant. Table 9 describes the performance of these membranes.
- Table 10 describes the performance of membranes made by treating an MPD-impregnated polysulfone substrate with a 1:1 mixture of ICIC and toluene diisocyanate (TDI) under the conditions of Examples 1-8, except that exposure time of the MPD-treated substrate to the mixture of (ICIC/TDI) is 2 minutes, and the drying time after (ICIC/TDI) treatment is 10 minutes before extraction.
- the molar ratio of (ICIC:TDI) in the mixture is 1:1.4, and the average functionality of the mixture is 2.42.
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Abstract
The present invention is directed to an improved reverse osmosis membrane that shows surprisingly improved solute rejection and permeation properties. The membrane includes a separating layer of a polyamideurea formed in situ by reaction of isocyanate-substituted acyl chloride and a diamine-treated microporous substrate.
Description
The present invention relates to composite membranes suitable for use in reverse osmosis processes such as the desalination of aqueous solutions. More particularly, the present invention relates to a multilayer membrane in which one layer is a copolymer of polyamideurea.
Reverse osmosis is a well-known process for purification of saline water. In this process, a pressure in excess of the osmotic pressure of the saline water feed solution is applied to the feed solution to separate purified water by use of a semipermeable premselective membrane. Purified water is thereby caused to diffuse through the membrane while salt and other impurities are retained by the membrane.
Permselective membranes include composite membranes that include a separating layer on a supporting microporous substrate. The substrate is typically supported on a support fabric to impart mechanical strength to the membrane. Permselective membranes suitable for use in reverse osmosis are available in various forms and configurations. Flat sheet, tubular and hollow fiber membranes are well-known in the art. These membranes can also vary in morphology. Homogenous and asymmetric membranes are operable, as well as thin film composites.
Permselective membranes are available in the form of multilayer structures that include a separating layer superimposed on a microporous polysulfone substrate layer. Membrane separating layers which may be employed include polyamides, polyphenylene esters, and polysulfonamides.
Polyamide discriminating layers are well-known in the art. The polyamide can be aliphatic or aromatic and may be crosslinked. Polyamide membranes may be made by the interfacial reaction of a cycloaliphatic diamine with isophthaloyl chloride, trimesoyl chloride or mixtures of these acid chlorides. Polyamide membranes also may be made by reaction of m-phenylenediamine and cyclohexane-1,3,5-tricarbonyl chloride. The polyamide discriminating layer also may be made by reaction of aromatic polyamines having at least two primary amines on an aromatic nucleus and aromatic polyfunctional acyl halides having an average of more than two acyl halide groups on an aromatic nucleus.
These prior art membranes have generally been useful as reverse osmosis membranes. These membranes, however, have been prone to deficiencies such as short useful life, low flux, and low salt rejection. A need therefore exists for improved reverse osmosis membranes which show both high rates of salt rejection while providing improved rates of flux.
The present invention is directed to an improved reverse osmosis membrane that shows surprisingly increased solute rejection and permeation properties. The membrane includes a separating layer of a polyamideurea formed in situ on a microporous support by reaction of an isocyanate-substituted acyl chloride with a diamine.
In accordance with the invention, improved reverse osmosis membranes are made by treating a microporous polymeric substrate with aqueous polyfunctional amine to provide an impregnated substrate. The substrate then is treated with a solution of isocyanate-substituted isophthaloyl chloride in a solvent that is non-reactive with the substrate to provide a membrane of polyamideurea in contact with the substrate.
The resulting membrane's surprisingly improved solute rejection and permeation properties enable the membrane to be employed in a wide variety of applications where high purity permeate is required. Examples of these applications include, but are not limited to, desalination of salt water, semiconductor manufacturing, reduction of BOD in waste water treatment, removal of dissolved salts during metal recovery, dairy processing such as milk processing, fruit juice concentration, and de-alcoholization of wine, beer, and the like. In such applications, the liquid is placed under pressure while in contact with the improved membranes of the invention to remove impurities.
Having briefly summarized the invention, the invention will now be described in detail by reference to the following specification and non-limiting examples. Unless otherwise specified, all percentages are by weight and all temperatures are in degrees centigrade.
Generally, the manufacture of the improved reverse osmosis membranes of the invention is accomplished by treating a microporous polymeric substrate with a solution of an aqueous polyfunctional amine, preferably a polyfunctional aromatic amine, and further treating the substrate with a solution of an isocyanate-substituted acyl chloride, such as 2-isocyanatoisophthaloyl chloride, 4-isocyanatoisophthaloyl chloride, 5-isocyanatoisophthaloyl chloride, 2-isocyanatoterephthaloyl chloride, 3,5-diisocyanatobenzyoyl chloride, 5-isocyanatocyclohexane-1,3-dicarbonyl chloride and 5-isocyanatoisophthaloyl bromide, preferably, 5-isocyanatoisophthaloyl chloride. The reaction of the isocyanate-substituted acyl chloride with the polyfunctional aromatic amine provides a novel composition of a polyamideurea that shows both surprisingly improved solute rejection and improved solvent flux.
Generally, isocyanate-substituted isophthaloyl chlorides may be prepared by reacting an amino-substituted isophthalic acid, or salts of amino-substituted isophthalic acid, catalyst, phosgene, and halogenated aliphatic solvent under elevated pressure and temperature. The 5-isocyanatoisophthaloyl chloride (ICIC) that is most preferably reacted with the diamine treated substrate is prepared by heating a mixture of 10 grams of 5-aminoisophthalic acid, a catalyst of 0.5 grams of imidazole, 60 grams of phosgene, and 50 ml of chlorobenzene solvent in a pressure vessel at 160° C. for 18 hours at under autogenous pressure. Removal of the solvent, followed by distillation of the product at 123°-128° C. and 0.2 mm Hg yields 8.8 grams of ICIC.
ICIC also may be produced by using alternatives to the preferred reactants mentioned above. For example, salts of 5-aminoisophthalic acid such as disodium 5-aminoisophthalate or 5-aminoisophthalic acid hydrochloride may be substituted for 5-aminoisophthalic acid. Similarly, imidazole may be replaced with other heteroatom-containing compounds capable of complexing phosgene. Examples of such catalysts include, but are not limited to pyridine, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and the like. Likewise, solvents such as dioxane or methylene chloride may be employed, so long as the solvent is reasonably unreactive with the reactants and products.
ICIC is most preferred as the isocyanato-substituted isophthaloyl chloride for reacting with the diamine-treated substrate to effect interfacial polymerization of polyamideurea. However, analogs such as 5-isocyanatoisophthaloyl bromide may be substituted for ICIC. Additionally, homologs such as 3,5-diisocyanatobenzoyl chloride and positional isomers of ICIC such as 4-isocyanatoisophthaloyl chloride may be substituted for ICIC. Aliphatic analogs, such as 5-isocyanatocyclohexane-1,3-dicarbonyl chloride may be employed as well. Also isocyanate-substituted isophthaloyl chloride may be employed in combination with a difunctional isocyanate to effect polymerization with a diamine to yield polyamideurea; 2,4-toluenediisocyanate is one example of such a diisocyanate. The isocyanate-substituted isophthaloyl chloride also may be employed in combination with a diacyl chloride to effect polymerization with a diamine to provide polyamideurea. Isophthaloyl chloride is an example of such a diacyl chloride.
Generally, the membranes of the present invention can be manufactured by first casting a suitable substrate for the membrane onto a support member. Suitable substrate layers have been described extensively in the art. Illustrative substrate materials include organic polymeric materials such as polysulfone, polyethersulfone, chlorinated polyvinyl chloride, styrene/acrylonitrile copolymer, polybutylene terephthalate, cellulose esters and other polymers which can be prepared with a high degree of porosity and controlled pore size distribution. These materials are generally cast onto a support of non-woven fabric or woven cloth, generally of polyester or polypropylene. Preferably, polysulfone is employed as the substrate. Porous inorganic materials also may be employed as the support material. Examples of such support compositions include porous glass, ceramics, sintered metals, and the like. These supports may be in the form of flat sheets, hollow tubes, hollow fibers, and the like to provide, for example, hollow fiber membranes.
Preparation of microporous polysulfone substrate films is well known in the art. Preparation includes casting a 15-20% solution of polysulfone in dimethylformamide (DMF) onto a glass plate, followed immediately by immersing the cast polysulfone into water to produce the polysulfone film. The side of the polysulfone film exposed to air during casting is called the "face" and contains very small pores, mostly under 200 angstroms in diameter. The "back" of the film in contact with the glass plate has very coarse pores.
After casting, the porous polysulfone substrate is treated with an aqueous solution of a polyfunctional diamine. Aqueous m-phenylenediamine (MPD) is preferred for treating the substrate. However, other diamines with sufficient water solubility to effect interfacial polymerization with isocyanato-substituted phthaloyl chlorides also may be employed. Examples of diamines include, but are not limited to, p-phenylenediamine, piperazine, m-xylylenediamine, and the like.
In the following, illustrative examples, the microporous polysulfone substrate is exposed to an aqueous solution of m-phenylenediamine (MPD) of indicated weight/volume (w/v) percent concentration at a temperature of 20° C. for 5 minutes. Advantageously 0.5 to 3% by weight, and most advantageously 1 to 2% by weight of aqueous MPD is employed. After exposure, the substrate is removed from the MPD solution, drained, and excess MPD solution removed via a rubber roller. The MPD-treated polysulfone substrate then is dipped into a solution of ICIC in a water-immiscible solvent under conditions suitable for effecting interfacial polymerization of polyamideurea of the general formula: ##STR1## where
m, n>0,
m+n≧3,
X=an (m+n)-valent organic group, and
Y=a divalent organic group.
Suitable solvents are solvents which do not deleteriously affect the substrate. Examples of solvents include, but are not limited to C5 -C8 n-alkanes, C5 -C8 fluoroalkanes, C2 -C8 chlorofluoroalkanes, C6 -C8 cyclo alkanes, C4 -C8 cyclo fluoroalkanes, and C4 -C8 cyclo chlorofluoro alkanes. Freon TF (1,1,2-trichlorotrifluoroethane) is the preferred solvent for use in the ICIC solution.
The concentration of the ICIC in the solution may vary depending on the specific solvent, substrate, and the like, and can be determined experimentally. Generally, concentrations of 0.03 to 5.0%, preferably 0.05 to 0.15 percent, can be employed.
After formation of the polyamideurea layer, the resulting membrane is removed from the ICIC solution and drip dried for 3 to 120 seconds, preferably 60 to 120 seconds, most preferably for 120 seconds. The membrane then is treated to extract impurities such as residual diamines, reaction by-products, residual ICIC, and the like. This is accomplished by exposing the membrane to water and then to aqueous lower alkanols. Water extraction is accomplished with running tap water at 20° to 60° C., preferably 40° to 60° C., most preferably 40°-45° C. for 1 to 20 minutes, preferably 5 to 10 minutes, most preferably 10 minutes. The aqueous lower alkanols are preferably C1 -C3 alkanols such as methanol, ethanol, isopropanol, and the like. The aqueous ethanol employed may be 5 to 25 percent ethanol, preferably 10 to 15 percent ethanol, most preferably 15 percent ethanol, the remainder being water. Generally, the aqueous ethanol is at 20° to 60° C., preferably 40° to 50° C., most preferably 50° C. The exposure time of the membrane to aqueous ethanol is 1 to 20 minutes, preferably 5 to 10 minutes, most preferably 10 minutes. The membrane then is rinsed with water to remove residual ethanol and is stored in deionized water until testing. Alternatively, the membrane may be impregnated with a wetting agent such as glycerine to provide for dry storage and subsequent rewetting.
The resulting membranes of polyamideurea on a polysulfone substrate are evaluated for salt rejection and flux by subjecting the membranes to a feed of aqueous 0.26%-0.28% NaCl at pH 6.8 and 25°-30° C. in a cross flow permeation cell. Membranes measuring 47 mm diameter are placed into the cell and exposed to 0.75 liters/minute of aqueous NaCl solution. The membranes are exposed to feed pressure of 420 psig for at least 14 hours, after which the feed pressure is lowered to 225 psig and the permeation properties determined.
The performance of the membrane is characterized in terms of the percent of salt NaCl rejected (R), permeability (Kw), and permeate productivity. The percent salt rejected (R) is defined as
R=(1-(C.sub.p /C.sub.f)·100%
where Cp and Cf are the concentrations of NaCl in the permeate and feed, respectively. The concentrations of the NaCl in the permeate and feed can be determined conductimetrically with a Beckman Gl conductivity cell (cell constant 1.0) and a YSI Model 34 conductivity meter.
The permeability (Kw) is defined as (flux/effective pressure), where flux is the flow rate of water through the membrane, and the effective pressure is equal to the feed pressure minus the opposing osmotic pressure. Flux is expressed in terms of permeate productivity, that is, in terms of gallons of permeate/square foot membrane area/day (gfd) at 225 psig and 25° C. Permeability is expressed in terms of meters/second/teraPascal (m/s/Pa×10-12). Conversion, expressed as volume of permeate per unit time divided by volume of feed per unit time is typically below 2%.
The membranes of the invention can be readily tailored to a specific application such as salt removal from drinking water, dairy processing, and the like by varying, for example, the concentration of the isocyanate substituted acyl halide employed to treat the diamine treated substrate. Accordingly, polyamideurea layers may be formed that are suitable for achieving salt rejections below 90 percent to more than 99 percent.
The membranes can be employed in a variety of devices known in the prior art. For example, flat sheets of the membrane can be utilized in either plate and frame, or spiral devices. Tubular and hollow fiber membranes can be assembled in generally parallel bundles in devices with tubesheets at opposing ends of the membranes. Radial, axial or down the bore flow feed can be utilized in hollow fiber devices.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. In the following examples, all temperatures are set forth in degrees centigrade; unless otherwise indicated, all parts and percentages are by weight.
A microporous polysulfone substrate is prepared by knife casting a 16% solution of UDEL P3500 polyethersulfone, supplied by Union Carbide Corp. in N,N-dimethylformamide (DMF) containing 0.3% water onto a support of polyester sailcloth. The solution is cast at a knife clearance of 5.5 mil. The sailcloth bearing the cast polyethersulfone solution is immersed in a water bath within two seconds of casting to produce a microporous polysulfone substrate. The substrate is washed in water to remove the N,N-dimethylformamide and is stored damp until use.
The microporous polysulfone substrate is immersed in an aqueous solution of MPD for five minutes. The substrate is drained briefly and then excess MPD droplets are removed by rolling the face of the substrate with a soft rubber roller. The damp MPD-impregnated substrate then is immersed in a solution of 5-isocyanatoisophthaloyl chloride in FREON TF solvent for 40 seconds to form a membrane of polyamideurea.
The membrane is removed from the ICIC solution and drip dried for 2 minutes. The membrane then is successively treated in 45° C., running tap water for ten minutes, and then in stirred 15% aqueous ethanol at 50° C. for 10 minutes. The membrane is stored in water containing 0.1% sodium bicarbonate until testing for permeability and flux.
The performance of membranes of examples 1-8 is reported in Table 1.
TABLE 1 ______________________________________ Ex- MPD ICIC Permeability Productivity ample Conc Conc % NaCl Kw (gfd @ # % % Rejection (m/s/TPa) 225 psig) ______________________________________ 1 1.00 0.05 99.22 6.62 19.0 2 1.50 0.05 99.34 5.41 15.5 3 2.00 0.05 99.33 8.66 24.8 4 1.00 0.15 99.06 3.16 9.0 5 1.00 0.10 98.99 4.46 12.8 6 1.50 0.10 99.44 5.86 16.8 7 2.00 0.15 99.42 3.66 10.5 8 1.50 0.15 99.22 2.92 8.4 ______________________________________
Examples 9-12 describe the use of n-hexane as the solvent for ICIC instead of FREON TF; all other conditions are identical to Examples 1-8. The results are reported in Table 2.
TABLE 2 ______________________________________ Ex- MPD ICIC Permeability Productivity ample Conc Conc % NaCl Kw (gfd @ # % % Rejection (m/s/TPa) 225 psig) ______________________________________ 9 1.00 0.05 99.27 4.14 11.8 10 1.50 0.05 99.22 4.77 13.6 11 2.00 0.05 99.18 5.68 16.2 12 1.50 0.15 99.49 3.55 10.1 ______________________________________
Examples 13-14 show the utility of the membranes of the invention for removing dissolved silica from the feed solution. In Examples 13-14, the amount of rejection of dissolved silica is determined for the membranes of Examples 3 and 6 by adding 170 ppm of sodium metasilicate nonahydrate to the 0.27% NaCl feed to give 36 ppm dissolved silica. Silica rejection is determined at 225 psig as described above for NaCl rejection. Silica concentration in the feed and permeate is determined by Method B of ASTM D 859. The results are given in Table 3.
TABLE 3 ______________________________________ Example # Membrane of Example Silica Rejection (%) ______________________________________ 13 3 99.59 14 6 99.39 ______________________________________
These examples illustrate the effect of feed pH on % NaCl and % silica rejection. The effect of feed pH is determined for the membranes of Examples 3 and 6 by adjusting the pH of a 0.27% NaCl/36 ppm Si2 feed solution with HCl and NaOH. The results are given in Table 4.
TABLE 4 __________________________________________________________________________ Membrane Feed Feed of Feed pH 6.8 Feed pH 4.1 pH 4.9 pH 7.4 Example Example NaCl SiO.sub.2 NaCl SiO.sub.2 NaCl NaCl # # Rej % Rej % Rej % Rej % Rej % Rej % __________________________________________________________________________ 15 3 99.52 99.59 92.52 99.56 98.00 99.48 16 6 99.46 99.39 91.46 99.47 97.46 99.49 __________________________________________________________________________
This example illustrates the surprising effectiveness of the membranes of the invention for desalination of seawater. In Example 17, the suitability of the membrane of Example 3 for seawater desalination is determined by changing the feed to 3.8% NaCl, pH 7 at 800 psig. The result is shown in Table 5.
TABLE 5 ______________________________________ Membrane of NaCl Permeability Productivity Example # Rejection Kw (m/s/TPa) (gfd @ 800 psig) ______________________________________ 3 99.28% 3.62 18.5 ______________________________________
Examples 18-20 show treatment of a polysulfone substrate with other aromatic amines that can serve to interfacially react with ICIC to produce the membranes of the invention. Table 6 describes membranes treated with p-phenylenediamine (PPD) that are contacted with ICIC. The membranes are made under the conditions employed in Examples 1-8 except that PPD is substituted for MPD. The performance of these membranes is given in Table 6.
TABLE 6 ______________________________________ Ex- PPD ICIC Permeability Productivity ample Conc Conc % NaCl Kw (gfd @ # % % Rejection (m/s/TPa) 225 psig) ______________________________________ 18 1.0 0.10 99.13 3.31 9.4 19 1.5 0.10 99.01 4.40 12.5 20 2.0 0.10 98.92 4.60 13.0 ______________________________________
These examples show the use of polyacyl halides in combination with ICIC to make the membranes of the invention. Table 7 describes membranes formed by treating an MPD-impregnated substrate made with 1:1 mixture of ICIC and 1,3,5-cyclohexanetricarbonyl chloride (CHTC) under the general conditions of Examples 1-8. The performance of the resulting membranes is given in Table 7.
TABLE 7 __________________________________________________________________________ MPD ICIC CHTC Example Conc Conc Conc % NaCl Permeability Productivity # % % % Rejection Kw (m/s/TPa) (gfd @ 225 psig) __________________________________________________________________________ 21 1.0 0.05 0.05 98.62 8.4 23.9 22 1.5 0.05 0.05 98.95 9.2 26.1 23 2.0 0.05 0.05 99.17 8.3 23.5 __________________________________________________________________________
These examples show that diacyl chlorides can be employed in combination with ICIC to form the membranes of the invention. Table 8 describes the performance of membranes made by treating an MPD impregnated polysulfone substrate with a 1:1 (wt) mixture of ICIC and isophthaloyl chloride (IC) under the conditions of Examples 1-8. The molar ratio of (ICIC:IC) in the mixture is 1:1.2, and the average functionally of the mixture is 2.45. The performance of the resulting membrane are shown in Table 8.
TABLE 8 __________________________________________________________________________ MPD ICIC IC Example Conc Conc Conc % NaCl Permeability Productivity # % % % Rejection Kw (m/s/TPa) (gfd @ 225 psig) __________________________________________________________________________ 24 1.0 0.05 0.05 98.73 4.9 14.0 25 1.5 0.05 0.05 99.56 5.5 15.6 26 2.0 0.05 0.05 98.68 5.9 16.7 __________________________________________________________________________
Examples 27 and 28 show the use of other aromatic diamines for treating the polysulfone substrate to provide a substrate that can be interfacially reacted with ICIC to make the polyamideurea membranes of the invention. In examples 27 and 28, piperazine and m-xylylenediamine are each substituted for MPD, respectively. ICIC is then reacted with the resulting substrate under the conditions of Examples 1-8. The diamines employed to treat the polysulfone substrate contain 1% triethylamine as an acid acceptor and 0.5% sodium lauryl sulfate as a surfactant. Table 9 describes the performance of these membranes.
TABLE 9 __________________________________________________________________________ Productivity Exple Amine ICIC % NaCl Permeability (gfd @ # Conc % Conc % Rejection Kw (m/s/TPa) 225 psig) __________________________________________________________________________ 26 piperazine 0.10 54.76 24.2 73.8 1.0 27 m-xylylenediamine 0.10 49.57 0.5 1.6 3.0 __________________________________________________________________________
These examples show that difunctional isocyanates can be combined with ICIC to make the membranes of the invention. Table 10 describes the performance of membranes made by treating an MPD-impregnated polysulfone substrate with a 1:1 mixture of ICIC and toluene diisocyanate (TDI) under the conditions of Examples 1-8, except that exposure time of the MPD-treated substrate to the mixture of (ICIC/TDI) is 2 minutes, and the drying time after (ICIC/TDI) treatment is 10 minutes before extraction. The molar ratio of (ICIC:TDI) in the mixture is 1:1.4, and the average functionality of the mixture is 2.42.
TABLE 10 __________________________________________________________________________ MPD ICIC TDI Example Conc Conc Conc % NaCl Permeability Productivity # % % % Rejection Kw (m/s/TPa) (gfd @ 225 psig) __________________________________________________________________________ 29 1.0 0.05 0.05 99.40 4.5 12.6 30 1.5 0.05 0.05 99.67 4.5 12.7 31 2.0 0.05 0.05 99.48 5.1 14 __________________________________________________________________________
The presence of both the isocyanate and acyl chloride functionality in the monomer employed to treat the diamine impregnated substrate is necessary to make a reverse osmosis membrane with the salt rejection properties of the membranes of the invention. The importance of these functionalities is demonstrated by Examples 32 and 33 in which MPD is interfacially polymerized with 2,4-toluenediisocyanate (TDI) and with isophthaloyl chloride (IC), respectively.
In examples 32-33, the conditions of Examples 1-8 are employed, except the time of exposure containing the MPD-treated substrate to the FREON TF solution of the second reactant is 30 seconds; also, no aqueous ethanol extraction is performed on the finished membrane. The results are shown in Table 11.
TABLE 11 __________________________________________________________________________ MPD TDI IC Example Conc Conc Conc % NaCl Permeability Productivity # % % % Rejection Kw (m/s/TPa) (gfd @ 225 psig) __________________________________________________________________________ 32 2.0 0.1 -- 15.87 30.4 100 33 2.0 -- 0.1 22.88 16.6 54 __________________________________________________________________________
These examples demonstrate that homologs of ICIC containing two isocyanato groups and one acyl chloride group, namely, 3,5-diisocyanatobenzoyl chloride (DIBC), will react interfacially with an aromatic diamine to make the polyamideurea membranes of this invention. The conditions of Examples 1-8 are employed, except that aqueous ethanol extraction is not performed on the finished membrane. The results are shown in Table 12.
TABLE 12 ______________________________________ Ex- MPD DIBC Permeability Productivity ample Conc Conc % NaCl Kw (gfd @ # % % Rejection (m/s/TPa) 225 psig) ______________________________________ 34 2.0 0.15 98.57 1.40 3.9 35 1.0 0.15 98.91 1.03 2.9 36 2.0 0.10 99.13 1.28 3.6 37 1.0 0.10 98.50 0.99 2.8 ______________________________________
The surprising efficacy of the mixed isocyanate-substituted acyl chloride which results in the polyamideurea of this invention is revealed in comparative Examples 1-4 in which 1,3,5-triisocyanatobenzene (TIB) is reacted interfacially with MPD to form a polyurea membrane. It is readily seen that the water flux and salt rejection of the polyurea membrane are inferior to the properties of the polyamideurea membrane of the invention. The conditions of Examples 1-8 are employed, except no aqueous ethanol extraction is performed on the finished membrane.
______________________________________ Ex- Per- Pro- am- MPD .[.DIBC.]..Iadd.TIB.Iaddend. % NaCl meability ductivity ple Conc Conc Re- Kw (gfd @ # % % jection (m/s/TPa) 225 psig) ______________________________________ 1 1.0 0.10 96.80 0.26 0.7 2 2.0 0.10 97.96 0.26 0.7 3 1.0 0.15 95.08 0.36 1.0 4 2.0 0.15 96.47 0.24 0.7 ______________________________________
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
Claims (7)
1. A reverse osmosis membrane that shows improved salt rejection, flux, and productivity, comprising a polyamideurea separating layer in contact with a .[.polysulfone.]. substrate, wherein said polyamideurea comprises the formula: ##STR2## where
m,n>0,
m+n≧3,
X=a (m+n) valent organic group, and
Y=a divalent organic group.
2. The membrane of claim 1 wherein said membrane has a percent salt rejection of at least about 90%.
3. The membrane of claim 1 wherein said membrane has a percent salt rejection of at least about 99%.
4. The membrane of claim 1 further comprising a support member for support said substrate having said separating layer thereon.
5. The membrane of claim 4 wherein said support member is selected from the group of porous glass, sintered metal, ceramics, polyolefins, polyesters, and polyamides.
6. The membrane of claim 3 wherein said support member is polyester.
7. The membrane of claim 1 wherein said membrane is in the form of a hollow fiber. .Iadd.8. The membrane of claim 1 wherein said substrate is a microporous substrate. .Iaddend. .Iadd.9. The membrane of claim 8 wherein said polyamide-urea is the reaction product of monoisocyanate-substituted aromatic diacyl halide and an aromatic diamine. .Iaddend. .Iadd.10. The membrane of claim 8 wherein said polyamide-urea is the reaction product of 1,3,5-substituted monoisocyanato isophthaloyl halide and meta or para-phenylenediamine. .Iaddend. .Iadd.11. The membrane of claim 8 wherein said polyamide-urea is the reaction product of ICIC and meta-phenylenediamine. .Iaddend. .Iadd.12. The membrane of claim 8 wherein said polyamide-urea is the reaction product of a diisocyanate-substituted aromatic acyl halide and an aromatic diamine. .Iaddend. .Iadd.13. The membrane of claim 1 wherein said substrate is made of polysulfone. .Iaddend. .Iadd.14. The membrane of claim 1 wherein X is a trivalent organic group. .Iaddend. .Iadd.15. The membrane of claim 14 wherein Y is a divalent meta- or para-substituted benzene group. .Iaddend. .Iadd.16. The membrane of claim 15 wherein X is a 1,3,5-substituted benzene group. .Iaddend. .Iadd.17. The membrane of claim 8 wherein said polyamide-urea is the reaction product of a trivalent, isocyanate-substituted acyl halide and a divalent cyclic amine. .Iaddend.
Priority Applications (1)
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US07/784,245 USRE34058E (en) | 1990-07-31 | 1991-10-29 | Multilayer reverse osmosis membrane of polyamide-urea |
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Application Number | Priority Date | Filing Date | Title |
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US07/560,512 US5019264A (en) | 1990-07-31 | 1990-07-31 | Multilayer reverse osmosis membrane of polyamide-urea |
US07/784,245 USRE34058E (en) | 1990-07-31 | 1991-10-29 | Multilayer reverse osmosis membrane of polyamide-urea |
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US07/560,512 Reissue US5019264A (en) | 1990-07-31 | 1990-07-31 | Multilayer reverse osmosis membrane of polyamide-urea |
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USRE34058E true USRE34058E (en) | 1992-09-08 |
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US07/784,245 Expired - Lifetime USRE34058E (en) | 1990-07-31 | 1991-10-29 | Multilayer reverse osmosis membrane of polyamide-urea |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070039874A1 (en) * | 2005-08-16 | 2007-02-22 | General Electric Company | Membranes and methods of treating membranes |
WO2009006295A2 (en) | 2007-06-28 | 2009-01-08 | Calera Corporation | Desalination methods and systems that include carbonate compound precipitation |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4366062A (en) * | 1978-02-13 | 1982-12-28 | Toray Industries, Inc. | Reverse osmosis using a composite isocyanurate membrane |
-
1991
- 1991-10-29 US US07/784,245 patent/USRE34058E/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4366062A (en) * | 1978-02-13 | 1982-12-28 | Toray Industries, Inc. | Reverse osmosis using a composite isocyanurate membrane |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070039874A1 (en) * | 2005-08-16 | 2007-02-22 | General Electric Company | Membranes and methods of treating membranes |
US7727434B2 (en) * | 2005-08-16 | 2010-06-01 | General Electric Company | Membranes and methods of treating membranes |
WO2009006295A2 (en) | 2007-06-28 | 2009-01-08 | Calera Corporation | Desalination methods and systems that include carbonate compound precipitation |
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