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 hollow fiber filtration membrane in which even when a relatively small contaminant having a size close to that of a permeation effective component is present in a filtration solution, Flux decrease over time during filtration is suppressed, and a useful component can be efficiently recovered, the hollow fiber filtration membrane including a polysulfone-based polymer and a hydrophilic polymer and having a large number of pores, the hollow fiber filtration membrane having a gradient asymmetric porous structure in which an average pore diameter of the pores increases from an outer surface portion toward an inner surface portion of the membrane, a content of the hydrophilic polymer of the membrane being from 6.0 to 10.0% by mass, a ratio between a content of the hydrophilic polymer at the inner surface portion and the content of the hydrophilic polymer of the membrane being in the range of from 0.50 to 0.80.

A porous membrane is made from a poly(phenylene ether) copolymer containing 10 to 40 mole percent repeat units derived from 2-methyl-6-phenylphenol and 60 to 90 mole percent repeat units derived from 2,6-dimethylphenol; and a block copolymer containing backbone or pendant blocks of poly(C.sub.2-4 alkylene oxide). The porous membrane is made by dissolving the poly(phenylene ether) copolymer in a water-miscible polar aprotic solvent to form a membrane-forming composition; and phase-inverting the membrane forming-composition in a first non-solvent composition to form the porous membrane. A method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, includes coextruding the membrane-forming composition through the annulus, and a first non-solvent composition through the bore, into a second non-solvent composition to form the hollow fiber.

Porous hollow fiber membranes having a low molecular weight cut-off, processes for their production, and their use for separation tasks in the fields of biotechnology, pharmaceutical technology and food processing.

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 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.

Disclosed are copolymers which are useful in hydrophilically modifying porous fluoropolymer supports. An example of the copolymers is: ##STR00001##
Also disclosed are a method of preparing such copolymers, a method of modifying porous fluoropolymer surfaces, and hydrophilic fluoropolymer porous membranes prepared therefrom. Also disclosed is a method of filtering fluids by the use of the hydrophilic fluoropolymer porous membranes.

The present invention provides a separation membrane that is usable at a high temperature and a high pressure. The solvent-resistant separation membrane of the present invention has an average pore diameter of the separation membrane surface of 0.005 to 1 μm and includes a portion where a degree of cyclization (I.sub.1600/I.sub.2240) as measured by the total reflection infrared absorption spectroscopy is 0.5 to 50.

A polyamide (PA) nanofiltration (NF) membrane and a preparation method thereof by regeneration from a scrapped microfiltration (MF) membrane are provided. The method adopts a cleaning-repairing-interfacial polymerization upgrading strategy, where, sodium hypochlorite and oxalic acid are used for deeply cleaning a scrapped MF membrane. PDA is used as a repairing agent to construct a reaction platform on the membrane surface, and finally a reaction system of piperazine and trimesoyl chloride (TMC) are used to form a PA NF membrane with a PA active layer. The repairing can construct a coating with a given thickness and prominent hydrophilicity on the membrane surface, which provides favorable base membrane conditions for upgrading and preparing an NF membrane.

Provided is a post-formation process for preparation of a highly permeable thin film composite membranes for reverse osmosis, particularly for use with brackish water at low energy conditions. The process includes contacting a polyamide discrimination layer of a TFC membrane with a solution containing an oxidizing agent to form a treated membrane, followed by contacting the treated membrane with a solution containing a reducing agent. The resulting membrane exhibits enhanced water flux while maintaining salt rejection. Also provided are reverse osmosis membranes prepared in accord with the method, and modules containing the highly permeable thin film composite membranes, and methods of purifying water using the membranes or modules.