Abstract: A method for removing ethylene from the atmosphere surrounding an agricultural product that is sensitive to ethylene, which promotes climacteric ripening and senescence, is disclosed. The method uses a membrane for selective ethylene permeation and removal from a container that is used to store, transport, and preserve the agricultural product.

Abstract: A humidification and selective permeation module in which humidification of a gaseous feed stream and selective permeation of components in the gaseous feed stream using a facilitated-transport membrane occurs within the same unit operation is disclosed. A process for separation of components in a gaseous feed stream using the humidification and permeation module combines continuous humidification of the feed stream and selective permeation using the facilitated-transport membrane.

Abstract: This invention discloses a method for separation of an aromatic compound from a mixture comprising an alkane using an improved thin-film composite membrane. The membrane is particularly useful for separation of benzene from cyclohexane, which have similar boiling points. The membrane comprises a more mechanically durable and defect-free separation layer as a result of its fabrication from an ionomer solution that is substantially free of dissolved ionic species not associated with the ionomer.

Abstract: Separation of linear and branched alkane isomers via selective permeation through a composite membrane is disclosed. The separation layer in the composite membrane is fabricated from a blend of at least two different fluoropolymer compositions, A and B, in which composition A has a normal-alkane isomer permeability that is greater than composition B. Composition B has a normal alkane to branched-alkane isomer selectivity that is equal or greater than composition A. The separation layer in the composite membrane has a normal-alkane permeability that is greater than composition B and a normal-alkane to branched alkane isomer selectivity that is greater than composition A.

Abstract: This invention discloses a thin-film composite membrane and process for the separation of carbon dioxide from non-hydrophilic gases such as methane, hydrogen, and nitrogen. The thin-film composite membrane has a gas-separation layer and a nonporous high-diffusion-rate layer, and has carbon dioxide to non-hydrophilic gas selectivity that is greater than the intrinsic selectivity of the gas-separation layer alone.

Abstract: This invention discloses a method for separation of an aromatic compound from a mixture comprising an alkane using an improved thin-film composite membrane. The membrane is particularly useful for separation of benzene from cyclohexane, which have similar boiling points. The membrane comprises a more mechanically durable and defect-free separation layer as a result of its fabrication from an ionomer solution that is substantially free of dissolved ionic species not associated with the ionomer.

Abstract: Membranes having a permselective active layer of a copolymerized perfluorinated monomer and an non-fluorinated alkylvinylester monomer demonstrate superior selective permeability performance for separating gas mixtures compared to membranes of exclusively perfluorinated polymers. Preferred active layer compositions are copolymers of perfluoro-2,2-dimethyl-1,3 dioxole (PDD) copolymerized with an alkylvinyl ester such as vinyl acetate, and vinyl pivalate, and with alkylvinyl esters that are substantially hydrolyzed to provide copolymerized vinyl alcohol functionality. The membranes can have a thin, high diffusion rate, “gutter layer” of a fluorinated polymer highly permeable to nitrogen positioned between the active layer and a porous support layer. A novel copolymer effective in selectively permeable membranes is a copolymer of PDD and an alkylvinyl ester compound having the formula H2C?CHOC(O)R1 in which R1 is a linear or branched alkyl group of from 2 to 5 carbon atoms.

Abstract: Separation of linear and branched alkane isomers via selective permeation through a composite membrane is disclosed. The separation layer in the composite membrane is fabricated from a blend of at least two different fluoropolymer compositions, A and B, in which composition A has a normal-alkane isomer permeability that is greater than composition B. Composition B has a normal alkane to branched-alkane isomer selectivity that is equal or greater than composition A. The separation layer in the composite membrane has a normal-alkane permeability that is greater than composition B and a normal-alkane to branched alkane isomer selectivity that is greater than composition A.

Abstract: Composite membranes comprised of at least two layers, one of the layers being a silver ionomer and a second layer which is a fluorinated polymer with certain permeability properties, are especially useful for the separation of alkanes from alkenes, Particularly useful is a three-layer composite membrane in which a porous layer is laminated to the second layer.

Abstract: A metal exchanged fluorinated ionomer is a copolymer minimally including repeating units of (i) a polymerized derivative of a perfluorinated cyclic or cyclizable monomer and (ii) a strong acid highly fluorinated vinylether compound in which the acid moiety is exchanged with a cation of a Group 11 metal. Metal exchanged fluorinated ionomers are readily soluble and can be formed into thin, selectively gas permeable membranes by solution deposition methods. These membranes are suitable for separating olefins from gas olefin/paraffin mixtures. Good selectivity and transmembrane flux can be obtained without humidifying the membrane feed gas mixture.

Abstract: Membranes having a permselective active layer of a copolymerized perfluorinated monomer and an non-fluorinated alkylvinylester monomer demonstrate superior selective permeability performance for separating gas mixtures compared to membranes of exclusively perfluorinated polymers. Preferred active layer compositions are copolymers of perfluoro-2,2-dimethyl-1,3 dioxole (PDD) copolymerized with an alkylvinyl ester such as vinyl acetate, and vinyl pivalate, and with alkylvinyl esters that are substantially hydrolyzed to provide copolymerized vinyl alcohol functionality. The membranes can have a thin, high diffusion rate, “gutter layer” of a fluorinated polymer highly permeable to nitrogen positioned between the active layer and a porous support layer. A novel copolymer effective in selectively permeable membranes is a copolymer of PDD and an alkylvinyl ester compound having the formula H2C?CHOC(0)R1 in which R1 is a linear or branched alkyl group of from 2 to 5 carbon atoms.

Abstract: Composite membranes comprised of at least two layers, one of the layers being a silver ionomer and a second layer which is a fluorinated polymer with certain permeability properties, are especially useful for the separation of alkanes from alkenes, Particularly useful is a three-layer composite membrane in which a porous layer is laminated to the second layer.

Abstract: Ionomers of Group 11 metals which include repeat units from vinylidene fluoride, can separate alkenes from alkanes when comprising a layer of a membrane. These membranes have excellent permeability and/or selectivity for alkenes in the separation of alkenes from alkanes.

Abstract: A system for providing nitrogen enriched air (NEA) from ambient air uses at least two gas separation membranes that are selectively gas permeable for oxygen and nitrogen. The oxygen/nitrogen selectivity and oxygen permeance of two of the membranes are different such that (1) the selectivity of first membrane is less than the second membrane and the oxygen permeance of first membrane is greater than the second membrane, or (2) the selectivity of first membrane is greater than the second membrane and the oxygen permeance of first membrane is less than the second membrane. The system is very compact, is energy efficient, and highly effective for generating NEA. It is ideally suited for mobile, remote and specialized end use applications, such as automotive vehicles, marine vessels, off-shore platform fuel storage and especially for supplying NEA to blanket ullage of onboard aircraft fuel storage tanks.

Abstract: A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

Abstract: A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

Abstract: A metal exchanged fluorinated ionomer is a copolymer minimally including repeating units of (i) a polymerized derivative of a perfluorinated cyclic or cyclizable monomer and (ii) a strong acid highly fluorinated vinylether compound in which the acid moiety is exchanged with a cation of a Group 11 metal. Metal exchanged fluorinated ionomers are readily soluble and can be formed into thin, selectively gas permeable membranes by solution deposition methods. These membranes are suitable for separating olefins from gas olefin/paraffin mixtures. Good selectivity and transmembrane flux can be obtained without humidifying the membrane feed gas mixture.

Abstract: A method of removing water from fluid mixtures of the water with other compounds uses selective vapor permeation or pervaporation of the water, as the case may be, from the mixture through a membrane having an amorphous perfluoropolymer selectively permeable layer. The novel process can be applied in such exemplary embodiments as (a) removing water from mixtures of compounds that have relative volatility of about 1-1.1 or that form azeotropic mixtures with water, (b) the dehydration of hydrocarbon oil such as hydraulic fluid to concentrations of water less than about 50 ppm, (c) removing water byproduct of reversible chemical equilibrium reactions to favor high conversion of reactants to desirable products, (d) drying ethanol to less than 0.5 wt. % water as can be used in fuel for internal combustion engines, and (e) controlling the water content to optimum concentration in enzyme-catalyzed chemical reactions carried out in organic media.

Abstract: A system for providing nitrogen enriched air (NEA) from ambient air uses at least two gas separation membranes that are selectively gas permeable for oxygen and nitrogen. The oxygen/nitrogen selectivity and oxygen permeance of two of the membranes are different such that (1) the selectivity of first membrane is less than the second membrane and the oxygen permeance of first membrane is greater than the second membrane, or (2) the selectivity of first membrane is greater than the second membrane and the oxygen permeance of first membrane is less than the second membrane. The system is very compact, is energy efficient, and highly effective for generating NEA. It is ideally suited for mobile, remote and specialized end use applications, such as automotive vehicles, marine vessels, off-shore platform fuel storage and especially for supplying NEA to blanket ullage of onboard aircraft fuel storage tanks.

Abstract: A method of removing water from fluid mixtures of the water with other compounds uses selective vapor permeation or pervaporation of the water, as the case may be, from the mixture through a membrane having an amorphous perfluoropolymer selectively permeable layer. The novel process can be applied in such exemplary embodiments as (a) removing water from mixtures of compounds that have relative volatility of about 1-1.1 or that form azeotropic mixtures with water, (b) the dehydration of hydrocarbon oil such as hydraulic fluid to concentrations of water less than about 50 ppm, (c) removing water byproduct of reversible chemical equilibrium reactions to favor high conversion of reactants to desirable products, (d) drying ethanol to less than 0.5 wt. % water as can be used in fuel for internal combustion engines, and (e) controlling the water content to optimum concentration in enzyme-catalyzed chemical reactions carried out in organic media.