Nanoporous selective sol-gel ceramic membranes, selective-membrane structures, and related methods are described. Representative ceramic selective membranes include ion-conductive membranes (e.g., proton-conducting membranes) and gas selective membranes. Representative uses for the membranes include incorporation into fuel cells and redox flow batteries (RFB) as ion-conducting membranes.

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.

Embodiments include methods of fabricating a zeolite-like metal-organic framework with an ana-topology (ana-ZMOF) thin film membrane, the methods comprising: (1) modifying a substrate with ana-ZMOF crystal precursors in the presence of polyvinylpyrrolidone; and (2) intergrowing the ana-ZMOF crystal precursors in the presence of polyvinylpyrrolidone to form a continuous defect-free thin film of an ana-ZMOF intergrown on the substrate. Embodiments further include methods of separating chemical species comprising contacting an ana-ZMOF thin film membrane with a fluid composition containing one or more chemical species and separating at least one of the chemical species.

The present invention relates to a composite semipermeable membrane including: a support membrane; and a separation functional layer provided on the support membrane, in which the separation functional layer comprises a plurality of protrusions formed of a thin membrane, and at least a part of the plurality of protrusions has a ratio (Wa/Wb) of larger than 1.3 in cross sections at arbitrary ten positions each having a length of 2.0 ?m in a membrane surface direction of the support membrane, provided that Wa is a maximum width of the protrusion and Wb is a root width of the protrusion.

A porous asymmetric membrane comprises a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer; and a polymer additive. A separation module can be fabricated from the porous asymmetric membrane. A method of forming the porous asymmetric membrane comprises: dissolving a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer and, a polymer additive in a water-miscible polar aprotic solvent to form a porous asymmetric membrane-forming composition; and phase-inverting the porous asymmetric membrane forming-composition in a first non-solvent composition to form the porous asymmetric membrane. The polymer additive comprises hydrophilic functional groups, copolymerized hydrophilic monomers, or blocks of hydrophilic monomer repeat units. For example, the polymer additive can comprise a hydrophilic polymer or amphiphilic polymer. The porous asymmetric membrane can be a flat membrane or hollow fiber.

A porous asymmetric membrane comprises a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer; and a polymer additive. A separation module can be fabricated from the porous asymmetric membrane. A method of forming the porous asymmetric membrane comprises: dissolving a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer and, a polymer additive in a water-miscible polar aprotic solvent to form a porous asymmetric membrane-forming composition; and phase-inverting the porous asymmetric membrane forming-composition in a first non-solvent composition to form the porous asymmetric membrane. The polymer additive comprises hydrophilic functional groups, copolymerized hydrophilic monomers, or blocks of hydrophilic monomer repeat units. For example, the polymer additive can comprise a hydrophilic polymer or amphiphilic polymer. The porous asymmetric membrane can be a flat membrane or hollow fiber.

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

This invention discloses a hollow fiber membrane and its preparation method and application, belonging to the field of membrane separation. The preparation method adopts a spinning device with a triple-orifice spinneret, including the casting solution, bore fluid and outer solution. The bore fluid, casting solution and outer solution are respectively co-extruded from the inner, middle and outer orifice of the spinneret, respectively, to form the nascent membrane. The nascent membrane is immersed in external coagulation bath to form a hollow fiber membrane. The outer solution and bore fluid are weakly-polar non-solvents of membrane-forming material and are water soluble. Based on the characteristics of the bore fluid and the outer solution, on the one hand, the mass exchange rate between solvents and non-solvents can be slowed down, the formation of dense skin is effectively avoided, and the surface porosity of the membrane is improved. On the other hand, the liquid film between solvents and non-solvents can finally dissolve in the coagulation bath without remaining in the hollow fiber membrane and spinning device. The hollow fiber membrane is prepared without double dense skins, and the surface porosity of the inner and outer surfaces of the hollow fiber membrane is improved, which is good for the improvement of membrane flux.

A method of forming a forward osmosis membrane having a porous substrate and a rejection layer is provided. The method comprises a) forming a thin film of a polymer solution on a suitable substrate, wherein the polymer solution contains at least one polymer and optionally one or more additives in a suitable solvent, b) immersing the thin film in a coagulant bath to form the porous substrate; and c) forming a rejection layer on the porous substrate. A forward osmosis membrane is also provided.

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.