A process for producing nitrogen-rich air by feeding high temperature air at 150 C. or more to an air separation membrane module is described. After being placed at 175 C. for two hours, the air separation module exhibits a shape-retention ratio of 95% or more in one embodiment. The nitrogen-rich air can be fed to a fuel tank for an aircraft, for example.

A process for producing nitrogen-rich air by feeding high temperature air at 150 C. or more to an air separation membrane module is described. After being placed at 175 C. for two hours, the air separation module exhibits a shape-retention ratio of 95% or more in one embodiment. The nitrogen-rich air can be fed to a fuel tank for an aircraft, for example.

Membrane materials and methods are disclosed for selectively separating or transporting ions in liquid media. In embodiments, the membranes comprise cellulose acetate polymer films having high cation, monovalent/divalent, and/or Li.sup.+/Mg.sup.2+ selectivity. Systems and methods for use of such membranes, including the direct extraction of lithium (DLE) from natural brines and other resources, also are disclosed.

The invention relates to a process for the production of membranes based on ethylene/chlorotrifluoroethylene polymers having a melting temperature not exceeding 200? C. The process relies on the diffusion induced phase separation of the ethylene/chlorotrifluoroethylene polymer from a solution and comprises the steps of providing a solution comprising an ethylene/chlorotrifluoroethylene polymer having a melting temperature not exceeding 200? C. in a solvent; casting the polymer solution into a film; immersing the film in a non-solvent bath to precipitate the polymer. Membranes made of compositions comprising an ethylene/chlorotrifluoroethylene polymer having a melting temperature not exceeding 200? C. and at least one second polymer are also disclosed.

A method of separating gas and a method of making a gas separation membrane. The method of separating gas includes flowing a gas stream through a membrane, in which the membrane comprises a crosslinked mixture of a poly(ether-b-amide) copolymer and an acrylate-terminated poly(ethylene glycol) according to formula (I) or formula (II); and separating the gas stream via the membrane.

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In formulas (I) and (II), each n is of from 2 to 30; and each R is independently H or CH.sub.3.

In an aspect, provided herein is an improved thin-film composite membrane and gas-separation processes using the composite membrane. The composite membrane incorporates a gutter layer from a polymer material selected from a substituted polyacetylene, an addition-polymerized and substituted polynorbornene, or an addition-polymerized and substituted polytricyclononene. The gutter layer provides improved adhesion with a gas-separation layer incorporating a fluorinated ionomer.

A process for producing nitrogen-rich air by feeding high temperature air at 150? C. or more to an air separation membrane module is described. After being placed at 175? C. for two hours, the air separation module exhibits a shape-retention ratio of 95% or more in one embodiment. The nitrogen-rich air can be fed to a fuel tank for an aircraft, for example.

An object of the present invention is to provide a porous hollow-fiber membrane having high strength while maintaining high pure-water permeation performance. A porous hollow-fiber membrane of the present invention is a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane, and a molecular chain of the fluororesin-based polymer is oriented in the longitudinal direction of the porous hollow-fiber membrane.

This composite hollow fiber membrane comprises a gas-permeable non-porous homogeneous layer which has a polyolefin resin (A) as the main component and a porous support layer which is made of a polyolefin resin (B) and which supports said non-porous homogeneous layer, and the composite hollow fiber membrane is characterized in that the polyolefin resin (A) of non-porous homogeneous layer is a block copolymer of ethylene units and at least one type of olefin unit selected from -olefin units having a carbon number of 3-20. By this means, a gas-permeable composite hollow fiber membrane is provided which has good gas permeability, reduces the impact of condensate on the performance of a gas dissolving module, and has excellent elution properties.

The present disclosure relates to a micro or nano porous membrane composed of a stretched membrane of a fluororesin membrane, wherein the fluororesin membrane contains sintered bodies of a plurality of core-shell particles containing fluororesins, wherein the core-shell particles include cores and shells covering outer surfaces of the cores, wherein an average particle size of the core-shell particles before being sintered is greater than or equal to 100 nm and less than or equal to 1,000 nm, wherein a ratio of a volume of the shells to a volume of the cores in the core-shell particles before being sintered is greater than or equal to 2/98 and less than or equal to 50/50, wherein a fluororesin of the cores is a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer or a combination thereof, and a fluororesin of the shells is polytetrafluoroethylene, and wherein a first heat of fusion of the fluororesins in the core-shell particles is less than or equal to 68 J/g.