The present invention relates to a method of preparing a perm-selective porous membrane and a method of separating gases using the prepared porous membrane. According to the present invention, a membrane is synthesized using a hierarchically structured alumina porous support by a counter diffusion method. During this synthesis, the diffusion rate of metal ions loaded on the porous support is controlled by controlling the pore size of the porous support, and the position at which the membrane is synthesized is controlled by synthesizing the membrane inside the support. This can increase the physical stability of the membrane and make the membrane thicker so as to ensure higher H.sub.2/CO.sub.2 separation factors.

The present invention relates to a BCDA-based semi-alicyclic homo- or co-polyimide membrane material for gas separation and a preparation method thereof. The polyimide material prepared according to the present invention has high solubility in casting solvents, particularly in polar organic solvents, by interrupting asymmetry in the polyimide chain structure and formation of polyimide complexes compared with aromatic polyimides, and has higher heat resistance than the conventional aromatic polyimides and aliphatic polyimides, so that it is useful for the process of a high-selective permeable composite membrane or a asymmetric hollow fiber membrane used for commercial purposes, suggesting that it can be effectively used as a membrane for gas separation in various fields. In addition, the polyimide material membrane for gas separation of the present invention is useful because it has superior gas separation properties to the conventional commercialized aromatic polyimides or semi-alicyclic polyimides.

The purpose of the present invention is to provide a composite semipermeable membrane having achieved both strength and water-permeable properties. This composite semipermeable membrane is provided with a substrate, a porous support body disposed on the substrate, and a separation function layer provided on the porous support body. The substrate has a structure provided with a crimped portion and a non-crimped portion. The porous support body is impregnated inside a crimped portion and inside a non-crimped portion of the substrate.

The invention relates to a process for recovering methane from digester biogas or landfill gas. More specifically, the invention pertains to a method for producing biomethane that removes impurities from a compressed digester biogas with staged membrane modules of at least two different types, to produce a biomethane having at least 94% CH.sub.4, below 3% of CO.sub.2, and below 4 ppm of H.sub.2S.

Provided herein are electrospun or electroblown non-woven fiber membranes, methods of making such membranes and lateral flow diagnostic devices comprising such membranes.

The present invention relates to a composite film comprising a graphene oxide coating layer, a porous polymer support comprising the same, and a method for preparing the same. More particularly, the present invention relates to a composite film comprising a graphene oxide coating layer with improved permeability and stability, a porous polymer support for a composite film comprising a graphene oxide coating layer with improved permeability, and a method for preparing the same.

This invention provides a new high flux reverse osmosis (RO) membrane comprising a nanoporous polyethersulfone (PES)/polyethylene oxide-polysilsesquioxane (PEO-Si) blend support membrane (PES/PEO-Si) comprising a polyethylene oxide-polysilsesquioxane (PEO-Si) polymer and a polyethersulfone (PES) polymer, a hydrophilic polymer inside the pores on the skin layer surface of the polyethersulfone/polyethylene oxide-polysilsesquioxane blend support membrane, and a thin, nanometer layer of cross-linked polyamide on the skin layer surface of said polyethersulfone/polyethylene oxide-polysilsesquioxane blend support membrane, and a method of making such a membrane. This invention also provides a method of using the new high flux reverse osmosis membrane comprising nanoporous PES/PEO-Si blend support membrane for water purification.

The present specification provides a composition for interfacial polymerization of polyamide including at least one of an amine compound and an acyl halide compound; a surfactant; and a compound represented by Chemical Formula 1, and a method for preparing a reverse osmosis membrane using the same.

The invention discloses dual layer-coated membranes and methods for making and using these membranes. The dual layer-coated membranes have a relatively porous and substantial void-containing selective asymmetric membrane support, a first coating layer comprising a hydrogel, and a second coating layer comprising a hydrophobic fluoropolymer. The membrane support has low selectivity and high permeance. The dual layer coating improves the selectivity of the membrane support and maintains the membrane performance with time. The dual layer-coated membranes are suitable for a variety of liquid, gas, and vapor separations such as water purification, non-aqueous liquid separation such as deep desulfurization of gasoline and diesel fuels, ethanol/water separations, pervaporation dehydration of aqueous/organic mixtures, fuel gas conditioning, CO.sub.2/CH.sub.4, He/CH.sub.4, CO.sub.2/N.sub.2, H.sub.2/CH.sub.4, O.sub.2/N.sub.2, olefin/paraffin, iso/normal paraffins separations, and other light gas mixture separations. The dual layer-coated membranes are especially useful for natural gas liquid (NGL) recovery and CO.sub.2 removal from natural gas.

The invention relates generally to forward osmosis membranes and methods of making forward osmosis membranes, in particular improved thin support layer upon which an active layer is cast.