The present invention relates to synthetic membranes and use of these synthetic membranes for isolation of volatile organic compounds and purification of water. The synthetic membrane includes a hydrophobic polymer layer located on a polymeric membrane support layer. The invention includes a method of isolating volatile organic compounds with the synthetic membrane by contacting a volatile organic mixture with the hydrophobic polymer layer of the synthetic membrane and removing volatile organic compounds from the polymeric membrane support layer of the synthetic membrane by a process of pervaporation. The invention also includes a method of purifying water with the synthetic membrane by contacting an ionic solution with the hydrophobic polymer layer of the synthetic membrane and removing water from the polymeric membrane support layer of the synthetic membrane by a process of reverse osmosis. The invention also relates to methods of isolating non-polar gases by gas fractionation.

Disclosed are porous membranes including a porous support and a coating comprising a copolymer having monomeric units A and B, and optionally monomeric units C; wherein A is a halogenated vinyl monomer other than tetrafluoroethylene, a halogenated alkyl vinyl ether, or an alkene of the formula C.sub.nH.sub.2n, wherein n is 1-6; B is a perfluoro (alkyl vinyl)ether compound, a perfluoroalkyl vinyl compound, or a perfluoro alkoxyalkyl vinyl ether compound, each compound having one or more sulfonic acid groups or a salt thereof, one or more sulfonyl fluoride groups, one or more sulfonamide groups, or one or more sulfonate ester groups, and C is vinylidene fluoride. Also disclosed are methods of preparing such porous membranes and methods of treating fluids by the use of these membranes.

Disclosed are porous membranes including a porous support and a coating comprising a copolymer having monomeric units A and B, and optionally monomeric units C; wherein A is a halogenated vinyl monomer other than tetrafluoroethylene, a halogenated alkyl vinyl ether, or an alkene of the formula C.sub.nH.sub.2n, wherein n is 1-6; B is a perfluoro (alkyl vinyl)ether compound, a perfluoroalkyl vinyl compound, or a perfluoro alkoxyalkyl vinyl ether compound, each compound having one or more sulfonic acid groups or a salt thereof, one or more sulfonyl fluoride groups, one or more sulfonamide groups, or one or more sulfonate ester groups, and C is vinylidene fluoride. Also disclosed are methods of preparing such porous membranes and methods of treating fluids by the use of these membranes.

A multistage membrane system and a process for treating a gas stream is provided in which the multistage membrane system comprises at least two membrane units wherein a first stage membrane unit comprises a polymeric membrane and a second membrane unit comprises a microporous zeolitic inorganic membrane or a combination of a microporous zeolitic inorganic membrane and a polymeric membrane.

Disclosed is a hollow fiber membrane module including a case and a hollow fiber membrane built in the case, wherein the hollow fiber membrane contains a polysulfone-based polymer and a hydrophilic polymer, and satisfies the following (A) and (B), and an amount of an eluted substance contained in a liquid obtained by circulating ultrapure water heated at 37° C. through a passage of an inner surface side of the hollow fiber membrane for 4 hours at 200 mL/min is 1.0 mg/m.sup.2 or less: (A) an insoluble component accounts for less than 3% by mass of the total mass of the hollow fiber membrane when the hollow fiber membrane is dissolved in N,N-dimethylacetamide; and (B) a flexible layer exists on a surface of a functional layer in a wet state and the flexible layer has a thickness of 7 nm or more. The present invention provides a hollow fiber membrane module including a hollow fiber membrane containing a polysulfone-based polymer and a hydrophilic polymer built therein, which elutes little eluted substance and exhibits high biocompatibility, while change in performance due to crosslinking of the hydrophilic polymer is suppressed.

Disclosed is a hollow fiber membrane module including a case and a hollow fiber membrane built in the case, wherein the hollow fiber membrane contains a polysulfone-based polymer and a hydrophilic polymer, and satisfies the following (A) and (B), and an amount of an eluted substance contained in a liquid obtained by circulating ultrapure water heated at 37° C. through a passage of an inner surface side of the hollow fiber membrane for 4 hours at 200 mL/min is 1.0 mg/m.sup.2 or less: (A) an insoluble component accounts for less than 3% by mass of the total mass of the hollow fiber membrane when the hollow fiber membrane is dissolved in N,N-dimethylacetamide; and (B) a flexible layer exists on a surface of a functional layer in a wet state and the flexible layer has a thickness of 7 nm or more. The present invention provides a hollow fiber membrane module including a hollow fiber membrane containing a polysulfone-based polymer and a hydrophilic polymer built therein, which elutes little eluted substance and exhibits high biocompatibility, while change in performance due to crosslinking of the hydrophilic polymer is suppressed.

Described herein are crosslinked graphene oxide based composite membranes that provide selective resistance for gases while providing water vapor permeability. Such composite membranes have a high water/air selectivity in permeability. The methods for making such membranes, and using the membranes for dehydrating or removing water vapor from gases are also described.

A method for making a gas separation membrane comprises dissolving and mixing poly(ether-b-amide) (Pebax) copolymer and acrylate-terminated polyethylene glycol oligomers (PEGDA) in a solvent, casting the polymer solution into a mold, removing the solvent to form a film, adding a photoinitiator to the film and irradiating the film with ultraviolet radiation to induce crosslinking of the PEGDA in the film, producing XLPEGDA, and submerging the film after exposure in a crosslinking solution to form crosslinked Pebax (XLPebax) in the film, wherein the crosslinking solution comprises one of a diisocyanate, a diisocyanate derivative and a combination of a diiscyanate and a diisocyanate derivative.

A method for making a gas separation membrane comprises dissolving and mixing poly(ether-b-amide) (Pebax) copolymer and acrylate-terminated polyethylene glycol oligomers (PEGDA) in a solvent, casting the polymer solution into a mold, removing the solvent to form a film, adding a photoinitiator to the film and irradiating the film with ultraviolet radiation to induce crosslinking of the PEGDA in the film, producing XLPEGDA, and submerging the film after exposure in a crosslinking solution to form crosslinked Pebax (XLPebax) in the film, wherein the crosslinking solution comprises one of a diisocyanate, a diisocyanate derivative and a combination of a diiscyanate and a diisocyanate derivative.

The present invention provides enthalpy exchanger elements (E, E′) and enthalpy exchangers comprising such elements. Furthermore, the invention discloses a method for producing such enthalpy exchanger elements and enthalpy exchangers, comprising the steps of a) providing an air-permeable sheet element (1); b) laminating at least one side (1a, 1b) of the sheet element (1) with a thin polymer film (3, 4) with water vapor transmission characteristics; and c) forming the laminated sheet element (1) into a desired shape exhibiting a three-dimensional corrugation pattern (5, 5, . . . ).