Described are liquid-flowable, porous polyethylene filter membranes that include two opposing sides and that have an asymmetric pore structure; filter components and filters that include this type of porous polyethylene filter membrane; methods of making the porous polyethylene filter membranes, filter components, and filters; and methods of using a porous polyethylene filter membrane, filter component, or filter, to filter a fluid such as a liquid chemical to remove unwanted material from the fluid.

Hollow fiber membranes, membrane contactors, and related production and use methods. The membranes include a substrate having a multiplicity of pores and a skin layer overlaying the porous substrate. The porous substrate includes a first semi-crystalline thermoplastic polyolefin (co)polymer resin and a nucleating agent in an amount effective to achieve nucleation. The skin layer includes a second semi-crystalline thermoplastic polyolefin (co)polymer resin derived by polymerizing at most 98 wt. % of 4-methyl-1-pentene monomer with at least 2 wt. % of linear or branched alpha olefin monomers. Preferably, the first thermoplastic polyolefin (co)polymer is different from the second thermoplastic polyolefin (co)polymer. The skin layer is less porous than the porous substrate and forms an outer surface of the hollow fiber with the porous substrate forming an inner surface. The hollow fibers are formed by co-extruding the porous substrate resin and the skin layer resin through an annular die.

A process for removing metal ions from aqueous systems is disclosed comprising the treatment of the aqueous system with a membrane M, wherein the membrane M has a molecular weight cut-off above 3,000 Da and comprises A.) a carrier membrane CM, wherein said carrier membrane CM has a porous structure wherein the average pore diameter on one surface is smaller than in the rest of the membrane, thus forming rejection layers R on one side of carrier membrane CM, and B.) an active layer A comprising at least one polymer P comprising a plurality of functional groups G capable of forming stable complexes with metal ions selected from Ca, Mg, Al, Cu, Ni, Pb, Zn, Sb, Co, Cr, Cd, Hg and/or Ag, wherein said active layer A is located on the surfaces of the rejection layers R of carrier membrane CM and throughout the porous structure of carrier membrane CM.

A carbonized PVDC copolymer useful for the separation of an olefin from its corresponding paraffin may be made by heating a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 20 micrometers to a pretreatment temperature of 100° C. to 180° C. to form a pretreated polyvinylidene chloride copolymer film and then heating the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350° C. to 750° C. A process for separating an olefin from its corresponding paraffin in a gas mixture is comprised of flowing the gas mixture through the aforementioned carbonized polyvinylidene chloride (PVDC) copolymer to produce a permeate first stream having an increased concentration of the olefin and a second retentate stream having an increased concentration of its corresponding paraffin.

A process for separating hydrogen from a gas mixture having hydrogen and a larger gas molecule is comprised of flowing the gas mixture through a carbonized polyvinylidene chloride (PVDC) copolymer membrane having a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 GPU hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity. The carbonized PVDC copolymer may be made by heating and restraining a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 250 micrometers to a pretreatment temperature of 100° C. to 180° C. to form a pretreated polyvinylidene chloride copolymer film and then heating and restraining the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350° C. to 750° C.

Embodiments of the present invention relate to a nanofiltration composite membrane for use to purify water, the methods for preparing said nanofiltration composite membranes and to the nanofiltration composite membranes prepared accordingly.

The present disclosure provides a hydrophilic, integrally asymmetric, semi-permeable hollow-fiber membrane made from a hydrophobic aromatic sulfone polymer and at least one hydrophilic polymer, the membrane comprising an inner surface facing towards its lumen, an outer surface facing outwards and an intermediate wall having a wall thickness and comprising an open-pore separating layer and an supporting layer having an asymmetric, sponge-like structure without finger pores, wherein adjoining to the wall of the inner surface the hollow-fiber membrane comprises an essentially isotropic zone; after which the pore size abruptly start increasing up to a maximum, after which the pore size decrease again, then adjoining an essentially isotropic supporting layer which then is adjoined by the outer surface, wherein the separating layer has a cut-off of greater than 300 000 Daltons. The present disclosure further provides a method for producing such membranes and a use of the membranes for microfiltration purposes.

A filter membrane includes a membrane having through holes that selectively separates specific material in processing medium, the membrane including first, second and third layers such that the first layer has first surface that is supplied with processing medium, the third layer has second surface on the opposite side of the first surface, and the second layer is formed between the first and third layers. The first layer includes first convex and concave portions, the third layer includes second convex and concave portions each having a larger area than each first concave portion, the second convex portions are formed to surround the second concave portions and connected to one another, the second layer has through holes connecting the second concave portions and first set of the first concave portions, and the first concave portions include second set in regions opposing the second convex portions that is connected to each other.

A process is provided of making facilitated transport membrane comprising a relatively hydrophilic, very small pore, nanoporous support membrane, a hydrophilic polymer inside the very small nanopores on the skin layer surface of the support membrane, a thin, nonporous, hydrophilic polymer layer coated on the surface of the support membrane, and metal salts incorporated in the hydrophilic polymer layer coated on the surface of the support membrane and the hydrophilic polymer inside the very small nanopores. In addition, the process provides a new method of making facilitated transport membrane spiral wound elements or hollow fiber modules for olefin/paraffin separations, particularly for C3=/C3 and C2=/C2 separations.

Hydrophobic poly(4-methyl-1-pentene) hollow fiber membrane for retention of anesthetic agents with an inner and an outer surface and between inner and outer surface an essentially isotropic support layer with a sponge-like, open-pored, microporous structure free of macrovoids and adjacent to this support layer on the outer surface a dense separation layer with a thickness between 1.0 and 3.5 μm. The membrane has a porosity in the range of greater than 35% to less than 50% by volume and a permeance for CO.sub.2 of 20-60 mol/(h.Math.m.sup.2.Math.bar), a gas separation factor α(CO.sub.2/N.sub.2) of at least 5 and a selectivity CO.sub.2/anesthetic agents of at least 150.

The process for producing this membrane is based on a thermally induced phase separation process in which process a homogeneous solution of a poly(4-methyl-1-pentene) in a solvent system containing components A and B is formed, wherein component A is a strong solvent and component B a weak non-solvent for the polymer component. After formation of a hollow fiber the hollow fiber is cooled in a liquid cooling medium to form a hollow fiber membrane. The concentration of the polymer component in the solution may be in the range from 42.5 to 45.8 wt.-% and the hollow fiber leaving the die runs through a gap between die and cooling medium with a gap length in the range of 5-30 mm.