To provide a membrane electrode assembly which is excellent in strength and is capable of reducing the electrolysis voltage when applied to a water electrolysis apparatus, and such a water electrolysis apparatus.

The membrane electrode assembly of the present invention is a membrane electrode assembly for use in a water electrolysis apparatus, comprising an anode having a catalyst layer, a cathode having a catalyst layer, and a polymer electrolyte membrane disposed between the anode and the cathode, wherein the polymer electrolyte membrane comprises a fluorinated polymer having ion exchange groups, and a woven fabric, the aperture ratio of the woven fabric is at least 50%, the denier number of warp yarns and the denier number of weft yarns, constituting the woven fabric, are each independently at least 2, and a relationship of Y≤240X−170 is satisfied where the membrane thickness of the polymer electrolyte membrane is Y μm, and the ion exchange capacity of the fluorinated polymer is X meq/g dry resin.

The present invention relates to a bipolar ion exchange membrane and a production method therefor, and provides a bipolar ion exchange membrane comprising a first polar heterogeneous ion exchange membrane and a second polar homogeneous ion exchange membrane stacked on each other, wherein the first polar heterogeneous ion exchange membrane is formed of an ion exchange resin powder and a binder resin that contain a first polar ion exchange group, the second polar homogeneous ion exchange membrane is formed of a matrix resin containing a second polar ion exchange group, and an interface between the first polar heterogeneous ion exchange membrane and the second polar homogeneous ion exchange membrane is a heterogeneous interface.

A bipolar membrane comprising a cation exchange mat of one or more cation exchange polymers, an anion exchange mat of one or more anion exchange polymers, and an internal 3D bipolar interface, disposed between the cation and anion exchange layers, including a mixture of at least one cation exchange polymer and at least one anion exchange polymer, such that an interface of the at least one cation exchange polymer and the at least one anion exchange polymer is the internal 3D bipolar interface that has a large area, and the at least one cation exchange polymer in the 3D bipolar interface is connected to the one or more cation exchange polymers of the cation exchange layer, and the at least one anion exchange polymer in the 3D bipolar interface is connected to the one or more anion exchange polymers of the anion exchange layer.

This invention relates to certain microporous articles comprising certain PEDEK-PEEK copolymers, to a method for making said microporous articles, in particular to a method of making microporous articles from a blend comprising said PEDEK-PEEK copolymer and at least one additional polymer, comprising processing said blend into a film and treating the film with a solvent for obtaining the microporous article.

The invention relates to a process for preparing an ester by alkoxycarbonylation of a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation and recycled into the reaction zone. In a development of the present invention, the ester thus formed is converted into another ester by transesterification.

A gas separation membrane for selective separation of hydrogen and helium from gas mixtures containing carbon dioxide includes a porous support layer, an aromatic polyamide layer on the porous support layer, and a coating including a glassy polymer formed on the aromatic polyamide layer. A glass transition temperature of the glassy polymer is greater than 50 C. The gas separation membrane may be formed by contacting a solution including the glassy polymer with an aromatic polyamide layer of a composite membrane and drying the solution to form a coating of the glassy polymer on the aromatic polyamide layer. Separating hydrogen or helium from a gas stream including carbon dioxide includes contacting a gas feed stream including carbon dioxide with the gas separation membrane to yield a permeate stream having a concentration of helium or hydrogen that exceeds the concentration of helium or hydrogen, respectively, in the gas feed stream.

A gas separation membrane for selective separation of hydrogen and helium from gas mixtures containing carbon dioxide includes a porous support layer, an aromatic polyamide layer on the porous support layer, and a coating including a glassy polymer formed on the aromatic polyamide layer. A glass transition temperature of the glassy polymer is greater than 50 C. The gas separation membrane may be formed by contacting a solution including the glassy polymer with an aromatic polyamide layer of a composite membrane and drying the solution to form a coating of the glassy polymer on the aromatic polyamide layer. Separating hydrogen or helium from a gas stream including carbon dioxide includes contacting a gas feed stream including carbon dioxide with the gas separation membrane to yield a permeate stream having a concentration of helium or hydrogen that exceeds the concentration of helium or hydrogen, respectively, in the gas feed stream.

The invention relates to a process for recovering methane from digester biogas or landfill gas. More specifically, the invention pertains to a method for producing biomethane that removes impurities from a compressed digester biogas with staged membrane modules of at least two different types, to produce a biomethane having at least 94% CH.sub.4, below 3% of CO.sub.2, and below 4 ppm of H.sub.2S.

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 H.sub.2CCHOC(O)R.sup.1 in which R.sup.1 is a linear or branched alkyl group of from 2 to 5 carbon atoms.

A method of concentrating a lithium-containing aqueous solution, the method comprising: (i) providing a water-permeable structure having an inner surface and outer surface, wherein at least said outer surface is coated with a water-permeable hydrophilic polymer having a thermal stability of at least 100 C.; and (ii) flowing a lithium-containing aqueous feed solution having an initial concentration of lithium over said inner surface while said outer surface is in contact with an aqueous draw solution containing a higher overall ion concentration than said lithium-containing aqueous feed solution, to result in forward osmosis of water from said lithium-containing aqueous feed solution to said aqueous draw solution, and wherein said forward osmosis results in a lithium-containing aqueous product solution having an increased concentration of lithium relative to the initial concentration of lithium in the lithium-containing aqueous feed solution.