A hollow-fiber membrane. The hollow-fiber membrane is made from a polymeric blend comprising an aromatic sulfone polymer and polyoxazoline; wherein the hollow-fiber membrane comprises an inner surface facing towards its lumen, an outer surface facing outwards and an intermediate wall having a wall thickness; wherein the hollow-fiber membrane is an integrally asymmetric, permeable hollow-fiber membrane.

Disclosed is a thin film composite hollow fiber that includes an outer support layer having a thickness of 10 to 1000 m and a polyamide thin film layer having a thickness of 1 to 10000 nm; and has a transmembrane pressure resistance rate of higher than 15 bar and a pure water permeability rate of higher than 0.8 Lm.sup.2h.sup.1bar.sup.1. Also disclosed are methods of preparing the above-described support and composite hollow fiber.

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.

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.

The present invention is related to a method for fabricating multilayer singlebore membranes (10) or multilayer multibore membranes (20) for ultrafiltration applications including the following method steps: (a) feeding at least a material of a substrate (12), at least one material of a functional layer (14, 15) and a bore fluid (36) to a spinneret (30) simultaneously; (b) forming said membranes (10, 20) as a tube-like string (54) in a one-step process in said spinneret (30); (c) thereby assigning a functionality to said functional layer (14, 15) applied on at least one surface (13, 17) of said substrate (12). The invention is also related to a spinneret (30) for fabricating multilayer singlebore membranes (10) or multilayer multibore membranes (20), using the inventive method, and to a system comprising such a spinneret (30).

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.

Embodiments of the present disclosure relate to methods of treating carbon molecular sieve (CMS) membranes, and in particular CMS hollow fiber membranes, that have undergone aging-induced permeance/permeability loss. By treating aged CMS membranes in accordance with embodiments of the present disclosure, the CMS membranes may be regenerated such that the aging-induced permeance/permeability loss is reversed and the permeance/permeability of the CMS membrane is increased. In some embodiments, the permeance/permeability of the treated CMS membrane may be increased to such a degree that the permeance/permeability of the regenerated CMS membrane is at least as high as the original permeance/permeability of the CMS membrane prior to aging-induced permeance/permeability loss.

In embodiments of the present disclosure, a CMS hollow fiber membranes may be prepared to have an ultrathin (e.g. 2 microns or less) separation layer. A precursor hollow fiber may be prepared as dual layer fibers having a thin sheath layer and a core layer. During pyrolysis, the sheath layer is transformed into an ultrathin separation layer. Porosity of the core layer substrate is well-maintained during pyrolysis, thereby enabling high permeance of the CMS hollow fiber membrane. Additionally, in some embodiments, the sheath layer of the precursor hollow fibers may be hybridized prior to pyrolysis. By hybridizing the sheath layer prior to pyrolysis, a CMS hollow fiber may having an improved separation factor, including for example increased carbon dioxide/methane selectivity, may be provided.

A carbon molecular sieve (CMS) membrane is made by pyrolyzing, to a peak pyrolysis temperature T.sub.P, a hollow fiber membrane having a polymeric sheath surrounding a polymeric core, anti-substructure collapse particles present in pores formed in the polymeric core help prevent collapse of pores formed in the hollow fiber membrane before pyrolysis. The anti-substructure collapse particles are made of a material or materials that either: i) have a glass transition temperature T.sub.G higher than T.sub.P, ii) have a melting point higher than T.sub.P, or ii) are completely thermally decomposed during said pyrolysis step at a temperature less than T.sub.P. The anti-substructure collapse particles are not soluble in a solvent used for dissolution of the polymeric material of the core.