Provided are certain membranes useful in the filtration of liquids and removal of various contaminants therein. In certain aspects the membranes have as one component a polyamide such as Nylon 11 and/or Nylon 12. Also provided is methodology for manufacturing such membranes and their use in filtration and purification of liquids. Membranes of the disclosure thus prepared exhibit superior acid stability when compared to polyamide membranes prepared from Nylon 6 or Nylon 6,6.

The present invention relates to a method of manufacturing a high-performance thin film composite (TFC) membrane through a solvent activation process. In the present invention, by using a mixed solvent of a good solvent and a poor solvent as an activating solvent, a conventional polysulfone-based support-based TFC membrane having high water permeance as well as excellent salt rejection may be manufactured.

Embodiments include nanofilms comprising the reaction product of a natural building block type A including at least two functional groups and a natural building block type B including at least three functional groups, wherein the natural building block type A and the natural building block type B react to form a branched polymer network including solvent-resistant bonds.

Described herein are polysulfone-based and polyether sulfone-based thin-film nanocomposite (TFNC) membranes produced by solution blow spinning (SBS) technology for forward osmosis applications, including desalination and wastewater treatment. These TFNC membranes exhibit ultra-fast water flux, low reverse salt flux, and fouling resistance.

Provided is a nanofiltration composite membrane, comprising: a supporting layer comprising a polyethylene terephthalate, a polymeric porous layer formed on the supporting layer, the polymeric porous layer comprising a polysulfone and an amphiphilic polymer represented by the formula below:

##STR00001##

and an interfacial polymerization layer formed on the polymeric porous layer and the interfacial polymerization layer comprising polyamide which is synthesized by polymerizing piperazine with 1,3,5-benzenetricarbonyl trichloride; wherein, n1, n2, n3, x, and y are integers greater than 0, the molecular weight of the amphiphilic polymer ranges from 90,000 to 200,000, and a weight ratio of the polysulfone to the amphiphilic polymer ranges from 2 to 20. The nanofiltration composite membrane can increase the removal rate of divalent ions and separate substances of specific molecular weights in solutions.

This forward-osmosis composite hollow fiber membrane module has hollow fiber bundles, wherein: the hollow fibers are each such that a separation active layer of a high-molecular polymer thin film is provided on the inner surface of a macroporous hollow fiber support film formed from a high-molecular polymer including polyketone; the film surface area of the hollow fiber bundles is 100 cm.sup.2 or greater; and the coefficient of variation of the average thickness of the separation active layer in the radial and thickness directions of the hollow fiber bundle is 0-60%, said coefficient being calculated through a method for measuring the mass of the separation active layer portion in a scanning electron microscope image in which a thickness-direction cross section of the separation active layer is imaged.

Apparatuses and methods for fabricating thin film composite hollow fiber membranes. In some implementations, an apparatus is used to remove excess first solution from a hollow fiber that has been immersed in a first solution. In some implementations, the method and apparatuses include flowing a gas, for example, compressed gas or ambient air, past a surface of a hollow fiber that has been immersed in a first solution prior to immersion in a second solution. In some implementations, the gas is flowed past the surface under positive pressure, while in other implementations the gas is flowed under negative pressure, for example, vacuum. The apparatuses and devices can be used to produce thin film composite hollow fiber membranes without pressing or damaging the hollow fiber.

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.

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 composite polyamide reverse osmosis membrane comprising a polyamide layer; where the polyamide layer has a thickness in the range of 50-250 nm, and large open spaces (i.e., free volumes); where the open spaces are defined by a ratio of water flux, J.sub.w, (gfd) divided by the average surface roughness, Ra, (nm) of the polyamide layer; wherein the composite polyamide reverse osmosis membrane has the ratio of J.sub.w/Ra>0.35 gfd/nm when tested at 65 psi, using an aqueous solution containing 250 ppm of NaCl; and a microporous support with a thickness ranging from 100-150 μm. The present invention also relates to processes of fabricating the composite polyamide reverse osmosis membrane.