The present invention provides an intrinsically anti-microbial hollow fiber membrane for filtration of liquids. The membrane comprises a plurality of porous hollow bilayer membrane fibers wherein the liquid enters from outside of the fiber, passing through the porous membrane into the lumen of the fiber and coming out from the hollow ending of the fiber, wherein this configuration provides a liquid outside-in arrangement and retains the filtrate outside. It means that membrane of the invention has built in characteristics to act against microbes in order to provide the use with a safe liquid free from microbes. The outer side or outer wall of the hollow fibers may be configured to become hydrophobic whereas inner side or inner wall of the hollow fiber membrane may be configured to become hydrophilic to enhance the water permeability to a great extent. The hollow fiber membrane may be configured to give it an intrinsic anti-microbial capability. A device containing above said membrane has also been disclosed.

A composite separation membrane is disclosed prepared by forming a separation layer on a surface of a porous support membrane, characterized in that the porous support membrane contains 50% by mass or more of polyphenylene ether; that the separation layer is constituted from a first separation layer and a second separation layer; that the first separation layer is formed with a thickness of from 50 nm to 1 m on the surface of the porous support membrane and is a sulfonated polyarylene ether copolymer which comprises a repeated structure of a specific hydrophobic segment and a specific hydrophilic segment; and that the second separation layer is formed with a thickness of from 1 nm to less than 50 nm on a surface of the first separation layer and is an alternately-layered product constituted from one or more kinds of ionomers.

A composite separation membrane is disclosed prepared by forming a separation layer on a surface of a porous support membrane, characterized in that the porous support membrane contains 50% by mass or more of polyphenylene ether; that the separation layer is constituted from a first separation layer and a second separation layer; that the first separation layer is formed with a thickness of from 50 nm to 1 m on the surface of the porous support membrane and is a sulfonated polyarylene ether copolymer which comprises a repeated structure of a specific hydrophobic segment and a specific hydrophilic segment; and that the second separation layer is formed with a thickness of from 1 nm to less than 50 nm on a surface of the first separation layer and is an alternately-layered product constituted from one or more kinds of ionomers.

Nitrogen is removed from biogas using a three-stage separation system based on gas separation membranes. The first stage separates a biomethane feed stream into a first permeate gas stream and a first retentate gas stream. The second stage separates the first permeate stream into a biomethane product gas and a first low quality biomethane gas stream. The third stage separates the first retentate into a second low quality biomethane gas stream and a waste gas. A biogas feed stream is pretreated to remove amounts of water, VOCs, and CO.sub.2 to yield a methane-enriched biogas stream. The methane-enriched biogas stream is compressed together with the first and second low quality biomethane gas streams to form the biomethane feed stream.

A polymer membrane, methods of gas separation utilizing the polymer membrane, and methods of producing the polymer membrane are disclosed herein. The polymer membrane includes a crosslinked polyethylene glycol network polymer according to formula (I):

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A polymer membrane, methods of gas separation utilizing the polymer membrane, and methods of producing the polymer membrane are disclosed herein. The polymer membrane includes a crosslinked polyethylene glycol network polymer according to formula (I):

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A composite membrane for selectively pervaporating a first liquid from a mixture comprising the first liquid and a second liquid. The composite membrane includes a porous substrate comprising opposite first and second major surfaces, and a plurality of pores. A pore-filling polymer is disposed in at least some of the pores so as to form a layer having a thickness within the porous substrate. The polymer is more permeable to the first liquid than the second liquid but not soluble in the first liquid or the second liquid. The composite membrane may be asymmetric or symmetric with respect to the amount of pore-filling polymer throughout the thickness of the porous substrate.

A composite membrane for selectively pervaporating a first liquid from a mixture comprising the first liquid and a second liquid. The composite membrane includes a porous substrate comprising opposite first and second major surfaces, and a plurality of pores. A pore-filling polymer is disposed in at least some of the pores so as to form a layer having a thickness within the porous substrate. The polymer is more permeable to the first liquid than the second liquid but not soluble in the first liquid or the second liquid. The composite membrane may be asymmetric or symmetric with respect to the amount of pore-filling polymer throughout the thickness of the porous substrate.

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.

Membrane comprising a block copolymer comprising polyarylene ether blocks and polyalkylene oxide blocks, wherein said polyalkylene oxide blocks comprise at least one polyethylene oxide segment and at least one segment of at least one polyalkylene oxide that is different from polyethylene oxide.