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.

An air-impermeable water vapor transport membrane comprises an active layer on a microporous polymeric substrate. The active layer comprises a polyethylene-oxide containing copolymer and a polar protic solvent in an amount of about 3% to about 100% of copolymer weight in the active layer. Molecules of the protic solvent are bonded to the copolymer. The polar protic solvent reduces temperature-dependent variability in the water-vapor permeability of the membrane.

An air-impermeable water vapor transport membrane comprises an active layer on a microporous polymeric substrate. The active layer comprises a polyethylene-oxide containing copolymer and a polar protic solvent in an amount of about 3% to about 100% of copolymer weight in the active layer. Molecules of the protic solvent are bonded to the copolymer. The polar protic solvent reduces temperature-dependent variability in the water-vapor permeability of the membrane.

Provided is a porous membrane which has a high water permeability performance, a high blocking performance, and a durability performance against loads of long-term and high operation pressures, which are suitable for filtering applications. The porous membrane includes one surface to be on a side of a filtrate; and the other surface to be on a side of a liquid to be filtered, wherein a surface pore diameter index of the one surface is 2.5 or more, the surface pore diameter index being determined by dividing a pore diameter in a top surface by a pore diameter in a second top surface.

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.

Disclosed are a method for preparing a high-strength anti-pollution anti-bacterial hollow fiber nano-filtration membrane and a product prepared by the method. The method comprises: S1, a chemical crosslinking reaction: placing an ultra-filtration base membrane in an acidic aqueous solution of glucose or an aqueous solution of phytic acid for a chemical crosslinking reaction to obtain a nano-filtration membrane; S2, a neutralization reaction immersing the nano-filtration membrane obtained in step S1 in an aqueous solution of alkali for the neutralization reaction, then washing the membrane to be neutral; S3, loading inorganic antibacterial agent: placing the membrane obtained in step S2 in an inorganic anti-bacterial agent solution for complexation, thereby obtaining a high-strength anti-pollution anti-bacterial hollow fiber nano-filtration membrane.

The present invention provides a gel containing a crosslinked polymer having at least one selected from the group consisting of an acidic dissociative group, an acidic dissociative group in a salt form, and a derivative group of an acidic dissociative group, and a condensate of a compound represented by the following formula (I): Si{R.sup.1N(R.sup.2)(R.sup.3)}(OR.sup.4)(OR.sup.5)(R.sup.6) (wherein each group is as defined in the DESCRIPTION).

A novel or improved base film for impregnation, impregnated base film, product incorporating the impregnated base film, and/or related methods as shown, claimed or described herein.

A process for preparing a porous membrane containing a thermoplastic polymer, the process containing: (i) forming a film shaped compound containing the thermoplastic polymer and a water soluble polymer; and (ii) extracting the film shaped compound with a solvent mixture, thereby obtaining the porous membrane; wherein the thermoplastic polymer has pores with an average pore diameter <2000 nm, determined using Hg porosimetry according to DIN 66133, the thermoplastic polymer contains a polyurethane, wherein the polyurethane contains: 11 to 79% by weight of a mixture of a diol and a diisocyanate; and 21 to 89% by weight of the compound with two functional groups which are reactive towards isocyanate groups.

The invention relates to a self-supporting highly moisture-permeable heat-insulating aerogel film and a preparation method thereof. The aerogel film is a self-supporting single-layer film with a SiO.sub.2 porous skeleton structure, having a thickness of 150 m to 300 m, which increases an exchange rate of vapor by 50% to 200%, and reduces a heat conductivity coefficient by 50% to 90%. The preparation method includes the following steps: (1) preparation of a template; (2) hydrolysis of nano-cellulose; (3) preparation of an aerogel film; and (4) post-treatment of the aerogel film.