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 cation exchange membrane having a stable ion exchange performance during usage, being excellent in basic properties such as membrane resistance and ion transportation as well as strength, and useful for electrodialysis and a method for producing the same. The cation exchange membrane is composed of a polyvinyl alcohol copolymer including an anionic group-containing anionic polymer segment and a vinyl alcohol polymer segment, and having a microphase separation structure having a domain size (X) in a range from 0 nm<X≦150 nm. The method is composed of forming a membrane from a polyvinyl alcohol copolymer which is adjusted to contain salts in a proportion that the salt weight (C) relative to the polyvinyl alcohol copolymer weight (P) is [(C)/(P)] of 4.5/95.5 or lower.

Provided is a cation exchange membrane having a stable ion exchange performance during usage, being excellent in basic properties such as membrane resistance and ion transportation as well as strength, and useful for electrodialysis and a method for producing the same. The cation exchange membrane is composed of a polyvinyl alcohol copolymer including an anionic group-containing anionic polymer segment and a vinyl alcohol polymer segment, and having a microphase separation structure having a domain size (X) in a range from 0 nm<X≦150 nm. The method is composed of forming a membrane from a polyvinyl alcohol copolymer which is adjusted to contain salts in a proportion that the salt weight (C) relative to the polyvinyl alcohol copolymer weight (P) is [(C)/(P)] of 4.5/95.5 or lower.

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.

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 crosslinked copolymer is provided, which includes a copolymer crosslinked by a crosslinking agent. The copolymer is copolymerized of (a) styrene-based monomer, (b) monomer having conjugated double bonds or acrylate ester monomer, and (c) ammonium-containing heterocyclic monomer. The crosslinking agent is (d) ##STR00001##
or the product of the reaction between ##STR00002##
and (e) ##STR00003##
or a combination thereof. Z is ##STR00004##
wherein each R.sup.1 is independently H or C.sub.1-4 alkyl group, each R.sup.2 is independently H or C.sub.1-4 alkyl group, R.sup.3 is single bond, —O—, —S—, —CH.sub.2—, or —NH—. n is a positive integer. x is 1 to 12, y is 1 to 5, and z is 1 to 5.

A gas separation membrane, a method for making the gas separation membrane, and a method for using the gas separation membrane are provided. An exemplary gas separation membrane includes a polyether-block-polyamide (PEBA) matrix and a cross-linked network including functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles dispersed through the PEBA matrix.

The present invention provides a room-temperature selective swelling method of pore-forming used for preparing separation membranes, comprising: treating a dense membrane of an amphiphilic block copolymer by a composite swelling agent at 15-30° C. for 1 min-24 h, removing the residual solvent, then leaving the membrane at room temperature to dry, so as to obtain an amphiphilic block copolymer separation membrane with a bi-continuous porous structure, wherein the composite swelling agent is composed of 60-96% of a first swelling agent and 4-40% of a second swelling agent, the first swelling agent is an alcohol solvent, the second swelling agent is selected from any one or a mixture of two or more of toluene, styrene, tetrahydrofuran, 1,4-dioxane and so on. In the method of the invention, selective swelling can be achieved at room temperature, abating the energy consumption in membrane-forming process. The method has universality and can be widely used in the pore-forming process of various amphiphilic block copolymers. The swelling level and morphology can be controlled by adjusting the composition of the solvent in the swelling agent and the second swelling agent content in the swelling agent.

The present invention provides a room-temperature selective swelling method of pore-forming used for preparing separation membranes, comprising: treating a dense membrane of an amphiphilic block copolymer by a composite swelling agent at 15-30° C. for 1 min-24 h, removing the residual solvent, then leaving the membrane at room temperature to dry, so as to obtain an amphiphilic block copolymer separation membrane with a bi-continuous porous structure, wherein the composite swelling agent is composed of 60-96% of a first swelling agent and 4-40% of a second swelling agent, the first swelling agent is an alcohol solvent, the second swelling agent is selected from any one or a mixture of two or more of toluene, styrene, tetrahydrofuran, 1,4-dioxane and so on. In the method of the invention, selective swelling can be achieved at room temperature, abating the energy consumption in membrane-forming process. The method has universality and can be widely used in the pore-forming process of various amphiphilic block copolymers. The swelling level and morphology can be controlled by adjusting the composition of the solvent in the swelling agent and the second swelling agent content in the swelling agent.

Methods of making a poly(propylenimine) (PPI) sorbent, a PPI sorbent, structures including the PPI sorbent, methods of separating CO.sub.2 using the PPI sorbent, and the like, are disclosed.