A solution is to produce an acid gas separation composite membrane provided with an acid gas separation facilitated membrane on a porous support, including; arranging of a coating liquid for acid gas separation formed through dispersing or dissolving into water a polyvinyl acetal compound formed through crosslinking, by an acetal bond, block copolymers formed through bonding of a polymer block formed of polyvinyl alcohol and a polymer block formed of polyacrylate through a linking group, an acid gas carrier and at least one kind of anion other than hydroxide ion, carboxyl ion, carbonate ion and bicarbonate ion, and coating of the coating liquid for acid gas separation onto a hydrophobic surface of the porous support having hydrophobicity at least on one surface to form the acid gas separation facilitated transport membrane thereon.

Provided is a facilitated CO.sub.2 transport membrane having improved CO.sub.2 permeance and improved CO.sub.2 selective permeability. The facilitated CO.sub.2 transport membrane includes a separation-functional membrane comprising a hydrophilic polymer gel membrane which contains a CO.sub.2 carrier and a CO.sub.2 hydration catalyst, wherein the hydrophilic polymer is a copolymer including a first structural unit derived from an acrylic acid cesium salt or an acrylic acid rubidium salt and a second structural unit derived from vinyl alcohol. More preferably, the CO.sub.2 hydration catalyst has catalytic activity at a temperature of 100° C. or higher.

A process and system for separating paraxylene from a mixture of paraxylene, metaxylene, orthoxylene, and ethylbenzene in a simulated moving bed apparatus using a membrane to separate non-aromatics from a desorbent stream. The lower nonaromatics content in the desorbent improves paraxylene product purity, increases paraxylene production at the same desorbent rate, reduces the desorbent rate, and/or reduces energy consumption in the product tower.

A steam permselective membrane containing a crosslinked hydrophilic polymer is provided. The steam permselective membrane may further contain at least one alkali metal compound selected from the group consisting of a cesium compound, a potassium compound and a rubidium compound.

Provided are a CO.sub.2 gas separation membrane, a method for manufacturing the same, and a carbon dioxide gas separation membrane module including the same, the CO.sub.2 gas separation membrane including: a first layer (A) containing at least one alkali metal compound selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate and an alkali metal hydroxide, and a first resin in which a polymer having a carboxyl group has been crosslinked; a second layer (B) containing at least one of the alkali metal compounds, and a second resin having a structural unit derived from a vinyl ester of a fatty acid; and a hydrophobic porous membrane (C).

The present invention provides a composition containing the following components (A)-(C): (A) an alkali metal compound, (B) a polymer having an acidic dissociative group, and (C) a compound having an acidic dissociative group and an amino group, and having β of more than 0.0 and less than 1.0 as calculated by the formula (I): β={amount (mol) of alkali metal in component (A)−amount (mol) of acidic dissociative group in component (B)}/amount (mol) of acidic dissociative group in component (C).

The present invention provides a composition for a CO.sub.2 gas separation membrane containing: at least one compound selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, and an alkali metal hydroxide; a crosslinked polymer in which a polymer having a carboxyl group has been crosslinked; and a non-crosslinked polymer obtained by polymerization of one or more monomers selected from the group consisting of vinyl acetate, acrylic acid, methacrylic acid, and a derivative thereof.

Membranes, methods of making the membranes, and methods of using the membranes are described herein. The membrane can comprise a support layer; and a selective polymer layer disposed (e.g., coated) on the support layer. The selective polymer layer can comprise a polymer matrix (e.g., a hydrophilic polymer, an amine-containing polymer, or a combination thereof), and a guanidine-based mobile carrier dispersed within the polymer matrix. Optionally, the selective polymer later can further include an amine-based mobile carrier, a CO.sub.2-philic ether, a graphene oxide, carbon nanotubes, or a combination thereof, dispersed within the polymer matrix. The membranes can be used to separate carbon dioxide from other gases, such as hydrogen and/or nitrogen. Also provided are methods of separating gas streams using the membranes described herein.

Provided herein are CO.sub.2-selective membranes that can be used to efficiently separate CO.sub.2 and CO. The membranes can be used to produce high-purity CO.sub.2 and CO gas streams from a feed gas stream comprising a mixture of CO.sub.2 and CO (e.g., an exhaust gas stream from a fuel cell, such as a solid oxide fuel cell). In this way, the membranes can be used with a solid oxide fuel cell system to covert CO.sub.2 to CO.

The present invention relates to a copolymer containing a constitutional unit derived from acrylic acid cesium salt or acrylic acid rubidium salt and a constitutional unit derived from vinyl alcohol, a resin composition containing the copolymer, a carbon dioxide gas separation membrane which can be manufactured with the resin composition, a carbon dioxide gas separation membrane module having the separation membrane, and a carbon dioxide gas separation apparatus including at least one type of the module.