This invention relates thin film nanocomposites (TFNCs) and methods of preparing the same by molecular layer-by-layer assembly. The TFNCs comprise a porous nanofibrous support first layer coated with a mid-layer having an outer separating layer, wherein the out separating layer has one or more bilayers or trilayers. The TFNCs can be particularly suitable for use as filtration membranes for the separation of dissolved components from fluids such as ultrafiltration, nanofiltration, and reverse osmosis. Thus, embodiments of the invention also include filtration systems and methods of filtering.

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.

A plurality of membrane elements are arranged in series within a pressure vessel in which at least two of the elements exhibit different permeances or selectivities for a gas or gas pair respectively.

Composite membrane tubing includes a porous scaffold support combined with polyether block amide copolymer. The composite membrane tubing has overlapping “fusion areas” that are an artifact of the manufacturing process. The methods of manufacturing above-mentioned composite membrane tubing have also been addressed. The composite membrane tubing can be reinforced with a structural mesh to further provide rigidity and strength. Composite membrane tubing or generally extruded tubing can be integrated into a multi-tube module for various applications.

Provided is a composition for interfacial polymerizing polyamide including an amine compound; and one or more types of compounds selected from among a purine-based compound and a pyrimidine-based compound of Chemical Formula 1: ##STR00001## wherein, in Chemical Formula 1: X is N or NH; Y is O or OH; Z is O, OH or NH.sub.2; R1 and R2 are each hydrogen or a substituted or unsubstituted alkyl group; and is a single bond or a double bond, and a method for manufacturing a water-treatment membrane and a water-treatment membrane using the same.

Provided is a composition for interfacial polymerizing polyamide including an amine compound; and one or more types of compounds selected from among a purine-based compound and a pyrimidine-based compound of Chemical Formula 1: ##STR00001## wherein, in Chemical Formula 1: X is N or NH; Y is O or OH; Z is O, OH or NH.sub.2; R1 and R2 are each hydrogen or a substituted or unsubstituted alkyl group; and is a single bond or a double bond, and a method for manufacturing a water-treatment membrane and a water-treatment membrane using the same.

A blood filtration device comprising a generally cylindrical housing having an interior wall. An interior member is mounted interior of the housing and comprises an outer surface having a porous membrane disposed thereon. The housing and interior member are relatively rotatable and define an annular gap therebetween. The blood filtration device also comprises an inlet for directing fluid into the annular gap, a first outlet for exiting filtrate passing through the membrane, and a second outlet for directing from the annular gap the remaining retentate. The porous membrane comprises a first layer and a second layer.

A blood filtration device comprising a generally cylindrical housing having an interior wall. An interior member is mounted interior of the housing and comprises an outer surface having a porous membrane disposed thereon. The housing and interior member are relatively rotatable and define an annular gap therebetween. The blood filtration device also comprises an inlet for directing fluid into the annular gap, a first outlet for exiting filtrate passing through the membrane, and a second outlet for directing from the annular gap the remaining retentate. The porous membrane comprises a first layer and a second layer.

A method of separating gas and a method of making a gas separation membrane. The method of separating gas includes flowing a gas stream through a membrane, in which the membrane comprises a crosslinked mixture of a poly(ether-b-amide) copolymer and an acrylate-terminated poly(ethylene glycol) according to formula (I) or formula (II); and separating the gas stream via the membrane. ##STR00001##
In formulas (I) and (II), each n is of from 2 to 30; and each R is independently —H or —CH.sub.3.