A membrane-forming dope for carbon membranes, comprising polyphenylene oxide in an amount giving a concentration of 15 to 40 wt. % in the membrane-forming dope, and sulfur in an amount giving a ratio of 0.1 to 5.0 wt. %, preferably 0.2 to 3.0 wt. %, of the total weight of the polyphenylene oxide and the sulfur, both of which are dissolved in a solvent that can dissolve these components. A hollow fiber carbon membrane is produced by molding the membrane-forming dope for carbon membranes in a hollow shape by means of a wet or dry-wet spinning method using a double tubular nozzle, subjecting the molded product to an infusibilization treatment by heating at 150 to 350? C. in the air, and then subjecting it to a carbonization treatment by heating at 600 to 800? C. in an inert atmosphere or under vacuum. When the product molded in a hollow shape by means of a wet or dry-wet spinning method is subjected to an infusibilization treatment by heating in the air while stretching the product with a stress of 0.002 to 0.005 MPa, a hollow fiber carbon membrane having excellent gas permeability and a further high gas separation factor (He/CH.sub.4) can be obtained.

In an aspect, provided herein is an improved thin-film composite membrane and gas-separation processes using the composite membrane. The composite membrane incorporates a gutter layer from a polymer material selected from a substituted polyacetylene, an addition-polymerized and substituted polynorbornene, or an addition-polymerized and substituted polytricyclononene. The gutter layer provides improved adhesion with a gas-separation layer incorporating a fluorinated ionomer.

A serial filtration system for liquid purification includes a preliminary-stage reverse-osmosis (RO) module and a first-stage, high-permeability, reverse-osmosis (HiRO) module. Both modules include (a) a chamber including an inlet, a retentate outlet, and a permeate outlet, and (b) at least one membrane separating the chamber into a retentate side on an upstream side of the membrane and a permeate side on a downstream side of the membrane. The membrane in the preliminary stage is an RO membrane, while the membrane in the first stage is an oxidized membrane. The first-stage inlet is in fluid communication with the preliminary-stage, retentate outlet; and the oxidized membrane in the first stage, comprises an oxidized polyamide active layer coated on a porous support, wherein the oxidized polyamide active layer has an atomic oxygen/nitrogen ratio of at least 1.5.

The organic-inorganic composite of the present invention includes an organic compound having a carbonyl group, an inorganic compound containing a metal component, and a silver component. The ratio of the number of metal atoms in the inorganic compound to the number of carbon atoms in the organic compound is from 0.04 to 1.60, and the ratio of the number of silver atoms in the silver component to the number of carbon atoms in the organic compound is from 0.07 to 0.55. The organic-inorganic composite may include, for example, an inorganic compound having a metal matrix structure containing a metal M and oxygen, an organic compound having a carbonyl group, and silver ions. The carbonyl group is bonded to a side chain R.sup.1 of the organic compound and has an end group R.sup.2.

The invention pertains to a process for the manufacture of a fluoropolymer hybrid organic/inorganic composite, to a polymer electrolyte membrane based on a said fluoropolymer and to uses of said electrolyte membrane in various applications, especially in electrochemical applications.

A ceramic membrane including a feed flow inlet, a retentate flow outlet, a permeate flow outlet, a membrane interface portion. The membrane interface portion include a feed flow channel fluidly coupled to the feed flow inlet and to the retentate flow outlet and permeate flow channel fluidly coupled to the retentate flow outlet, wherein the membrane interface portion is operable to allow for fluid communication between the feed flow channels and the permeate flow channels through a membrane portion, and wherein the ceramic membrane has an open porosity of at least 10%. Also provided is a process for preparing the ceramic membrane by additive manufacture.

The invention a solvent-resistant polymeric nanofiltration membrane and preparation method thereof. The method includes subjecting a diamine monomer and a dianhydride monomer to cyclization imidization in a first polar organic solvent at 160 to 230 C., to form a polyimide, wherein the diamine monomer includes a diamine monomer with a carboxyl group and a diamine monomer without a carboxyl group; dissolving the polyimide in a second polar organic solvent, to form a membrane-forming solution; performing phase inversion to obtain an intermediate membrane; treating the intermediate membrane with an organic solution of a metal salt, so that the metal ion is coordinated and cross-linked with the carboxyl group in the polyimide, to obtain a solvent-resistant polymeric nanofiltration membrane, wherein the metal salt is a divalent and/or a multi-valent metal salt. The invention also discloses use of the solvent-resistant polymeric nanofiltration membrane in the separation and/or purification of a compound.

Water treatment systems and methods are provided to beneficially use the concentrate stream for other, non-potable, use. Embodiments of the invention use the distribution pressure to drive the membrane process and are configured in line with household plumbing so the concentrate is directed through the treatment system but bypassing the treatment mechanism to other uses in the building. In embodiments of this system, only the purified water that is needed for potable consumption is extracted from the water with the rest proceeding to its intended destination at the same pressure.

The organic-inorganic composite of the present invention includes an organic compound having a carbonyl group, an inorganic compound containing a metal component, and a silver component. The ratio of the number of metal atoms in the inorganic compound to the number of carbon atoms in the organic compound is from 0.04 to 1.60, and the ratio of the number of silver atoms in the silver component to the number of carbon atoms in the organic compound is from 0.07 to 0.55. The organic-inorganic composite may include, for example, an inorganic compound having a metal matrix structure containing a metal M and oxygen, an organic compound having a carbonyl group, and silver ions. The carbonyl group is bonded to a side chain R.sup.1 of the organic compound and has an end group R.sup.2.

A method for preparing a homogeneous braid-reinforced (HMR) PPTA hollow fiber membrane combines PPTA hollow tubular braids with PPTA surface separation layer. The method includes following steps of: (1) preparing the PPTA hollow tubular braids, wherein the PPTA hollow tubular braids which are made from PPTA filament yarns are woven by a two-dimensional braided method, the outer diameter of the PPTA tubular braids is 1-2 mm; (2) preparing the PPTA casting solution as the surface separation layer, wherein the 1-3 wt % PPTA resin, 0-2 wt % inorganic particles and 10-20 wt % pore-forming agents are mixed into 75-89% inorganic acid solvent, stirred for 1-3 hours at 70 C.-90 C. to form homogeneous and transparent casting solution; and (3) preparing reinforced PPTA hollow fiber membrane, wherein the casting solution as the surface separation layer is evenly coated on the surfaces of the PPTA hollow tubular braids through spinneret, and they are immersed in a coagulation bath for solidified formation.