A thin micro-porous membrane sheet and filtering device using it is presented. The membrane sheet includes a thin porous metal sheet of thickness between 20 and 200 μm with a porous ceramic coating of thickness less than 25 μm on at least one of its surfaces. The porous metal sheet has mean pore sizes at micro and sub-micrometer level and has a surface substantially free of pores greater than 10 micrometers. The ceramic coating layer may be made of particles with a mean particle size in a range of 10 to 300 nm and contains certain sintering promoters. The ceramic coating is sintered with the metal sheet in non-oxidizing environment at lower temperatures than typical ceramic membranes. The thin membrane sheet is used to filter fine particulates from micrometers to nanometers from a liquid or gas stream. The thin membrane sheet may be assembled into a filter device having high surface area packing density and straight mini-flow channels.

A separation membrane structure includes a porous support, a first separation membrane and a second separation membrane. The first separation membrane is formed on the porous support and contains high silica zeolite having Si/Al atomic ratio of greater than or equal to 200. The second separation membrane is formed on the first separation membrane and contains cation.

Disclosed herein are compositions, systems, and methods of using dual-layer hollow fiber membranes. The compositions and systems of the disclosure can be used to desalinate water from an underground formation. The compositions and systems of the disclosure can be further used to capture carbon dioxide from a gaseous sample.

A method of fabricating a gas separation membrane includes providing a coextruded multilayer film that includes a first polymer layer formed of a first polymer material and a second polymer layer formed of a second polymer material, the first polymer material having a first gas permeability. The coextruded multilayer film is axially oriented such that the second polymer layer has a second gas permeability that is greater than the first gas permeability.

A membrane for fluid species transport includes a porous substrate and a selective-transport layer comprising 2-D-material flakes. The porous substrate defines surface pores with dimensions larger than 2 microns, and the selective-transport layer coats the porous substrate and spans across the surface pores. The porous substrate can be contacted with a liquid or coating to fill or coat the surface pores of the porous substrate. Next, a 2-D-material-flake solution is deposited on the porous substrate. Evaporation of solvent from the deposited 2-D-material-flake solution forms the selective-transport layer.

A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent, and a solvent is provided. The dissolvable polyimide is represented by formula 1: ##STR00001## wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A′ is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1≤X≤0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A dry phase inversion process is performed on the polyimide membrane.

A method suppresses membrane thickness variation and air resistance variation after a compression at 60° C. or 80° C. Stretching is performed at least twice in at least different axial directions before the extraction of the solvent, and at the same time, at least one of (i) and (ii) is satisfied. (i) The step (c) is a first stretching step of stretching the sheet-shaped product at least once in a sheet transport direction (MD direction) and at least once in a sheet width direction (TD direction) individually, and the MD stretching magnification and the TD stretching magnification in the step (c) satisfy (TD stretching magnification≥MD stretching magnification−2). (ii) The stretching temperature (T1) of a first axial stretching performed firstly in the step (c) and the maximal stretching temperature (T2) of a second stretching performed after the first axial stretching satisfy (T1−T2≥0).

A composition of five parts by mass of chitosan and one part graphene oxide is suspended in water. The composition may be used to form filtration layers of any size or shape and may be reinforced by additional layers. The composition may be used to construct a large filtration apparatus of any size or shape and may be used to form highly resilient, antimicrobial structures and surfaces for a variety of applications.

Methods of making blended, isoporous, asymmetric (graded) films (e.g. ultrafiltration membranes) comprising two or more chemically distinct block copolymers and blended, isoporous, asymmetric (graded) films (e.g. ultrafiltration membranes) comprising two or more chemically distinct block copolymers. The generation of blended membranes by mixing two chemically distinct block copolymers in the casting solution demonstrates a pathway to advanced asymmetric block copolymer derived films, which can be used as ultrafiltration membranes, in which different pore surface chemistries and associated functionalities can be integrated into a single membrane via standard membrane fabrication, i.e. without requiring laborious post-fabrication modification steps. The block copolymers may be diblock, triblock and/or multiblock mixes and some block copolymers in the mix may be functionally modified. Triblock copolymers comprising a reactive group (e.g., sulfhydryl group) terminated block and films comprising the triblock copolymers.

Provided is a moisture permeable filter medium formed by laminating a hydrophobic layer having hydrophobicity and a hydrophilic layer having hydrophilicity together, in which one of the hydrophobic layer and the hydrophilic layer is composed of a PTFE porous film formed using PTFE, and the other of the hydrophobic layer and the hydrophilic layer is composed of an air permeable sheet to which air is permeable.