Provided is a composite semipermeable membrane having a high salt removal rate and a high water permeability. The composite semipermeable membrane comprises a substrate, a porous support layer formed on the substrate, and a separation functional layer formed on the porous support layer, the hydrophilic macromolecule concentration on the substrate-side surface of the porous support layer being higher than that on the separation functional layer-side surface.

New carbon nanomaterials, preferably titanium carbide-derived carbon (CDC) nanoparticles, were embedded into a polyamide film to give CDC/polyamide mixed matrix membranes by the interfacial polymerization reaction of an aliphatic diamine, e.g., piperazine, and an activated aromatic dicarboxylate, e.g., isophthaloyl chloride, supported on a sulfone-containing polymer, e.g., polysulfone (PSF), layer, which is preferably previously prepared by dry/wet phase inversion. The inventive membranes can separate CO.sub.2 (or other gases) from mixtures of CO.sub.2 and further gases, esp. CH.sub.4, based upon the generally selective nanocomposite layer(s) of CDC/polyamide.

Embodiments described herein relate generally to durable graphene oxide membranes for fluid filtration. For example, the graphene oxide membranes can be durable under high temperatures non-neutral pH, and/or high pressures. One aspect of the present disclosure relates to a filtration apparatus comprising: a support substrate, and a graphene oxide membrane disposed on the support substrate. The graphene oxide membrane has a first lactose rejection rate of at least 50% with a first 1 wt % lactose solution at room temperature. The graphene oxide membrane has a second lactose rejection rate of at least 50% with a second 1 wt % lactose solution at room temperature after the graphene oxide membrane is contacted with a solution that is at least 80° C. for a period of time.

Provided are a CO.sub.2 gas separation membrane, a method for manufacturing the same, and a carbon dioxide gas separation membrane module including the same, the CO.sub.2 gas separation membrane including: a first layer (A) containing at least one alkali metal compound selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate and an alkali metal hydroxide, and a first resin in which a polymer having a carboxyl group has been crosslinked; a second layer (B) containing at least one of the alkali metal compounds, and a second resin having a structural unit derived from a vinyl ester of a fatty acid; and a hydrophobic porous membrane (C).

The composite anion exchange membrane includes: a surface layer on a single surface or both surfaces of an anion exchange membrane substrate, in which the above-described surface layer contains a copolymer of a monomer A which is a water-soluble polyfunctional monomer and a monomer B which is a cationic monomer, an anion exchange capacity of the above-described surface layer is 0.05 meq/cm.sup.3 to 0.50 meq/cm.sup.3, and an anion exchange capacity of the above-described anion exchange membrane substrate is 1.0 meq/cm.sup.3 to 5.0 meq/cm.sup.3.

A gas separation membrane has a gas separation layer containing a crosslinked cellulose resin. The crosslinked cellulose resin has a particular linking structure in a crosslinked structure. The gas separation layer contains an organic solvent in a particular amount.

The present invention refers to a surface coating of commercial polyamide (PA) membranes with graphene oxide (GO) using a technology that involves spin-coating with specific sequence of low and high rotation, interface phenomena provided by a set of materials containing ethyl alcohol in high concentration, as well as morphological characteristics and customized surface chemistry of GO, among other conditions that allow a differentiated technology to obtain an effective coating of GO on PA membrane.

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.

The present invention discloses a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof. The hollow fiber membrane comprises 30%-50% of polyvinylidene fluoride resin, 40%-60% of inorganic molecular solution in-situ pore-forming agent and 5%-20% of organic diluent. The preparation method comprises preparing the inorganic molecular solution in-situ pore-forming agent formed from organic sol, mixing the inorganic molecular solution in-situ pore-forming agent formed from the organic sol with high-molecular polymer resin and the organic diluent to obtain a material A,extruding hollow fibers through a forming mold, stretching on line by 2-3 times to obtain hollow fiber filaments, extracting the hollow fiber filaments with an organic solvent to remove all organic matters, removing inorganic matters dispersed in the hollow fiber filaments by using an acid or alkaline solution to form a porous membrane and cleaning the porous membrane, setting and performing heat treatment to obtain the polyvinylidene fluoride hollow fiber membrane.

The present invention relates to synthetic membranes and use of these synthetic membranes for isolation of volatile organic compounds and purification of water. The synthetic membrane includes a hydrophobic polymer layer located on a polymeric membrane support layer. The invention includes a method of isolating volatile organic compounds with the synthetic membrane by contacting a volatile organic mixture with the hydrophobic polymer layer of the synthetic membrane and removing volatile organic compounds from the polymeric membrane support layer of the synthetic membrane by a process of pervaporation. The invention also includes a method of purifying water with the synthetic membrane by contacting an ionic solution with the hydrophobic polymer layer of the synthetic membrane and removing water from the polymeric membrane support layer of the synthetic membrane by a process of reverse osmosis. The invention also relates to methods of isolating non-polar gases by gas fractionation.