Disclosed is the preparation of composite fluid separation membranes based on poly (aryl ether ketone) (PAEK) polymers with the separation layer formed by a layer-by-layer reticular synthesis. The porous PAEK substrate is semicrystalline, exhibits a mesoporous surface structure, and is surface functionalized. The separation layer formed by the hierarchical layer-by-layer process is in the form of a covalent organic network integrally linked via covalent bonds to the functional groups of the substrate. The composite separation layer may be synthesized in situ in a preformed separation device on the surface of the PAEK substrate. Device configurations include flat sheet, spiral wound, monolith, and hollow fiber configurations with the hollow fiber configuration being preferred. Hollow fibers are formed from PAEK polymers with poly (ether ether ketone) and poly (ether ketone) particularly preferred. Composite PAEK membranes of the present invention are useful for a broad range of fluid separation applications.

Disclosed herein are membranes comprising: porous substrate; and two or more graphene oxide (GO) sheets disposed on the porous substrate, each GO layer comprising a plurality of GO flakes, each GO flake comprising a planar graphene structure with oxygen moieties extending therefrom, wherein the membrane, when a pressure from 10 bar to 50 bar of transmembrane pressure is applied from 1 hour to 48 hours, has an aqueous flux wherein the aqueous flux changes by 5% or less while the pressure is applied. The membranes can also include an intercalating agent disposed between the two or more GO sheets, the intercalating agent interacting with each GO sheet, wherein the intercalating agent provides a non-covalent stabilization of the two or more GO sheets. Also disclosed herein are methods of making and using the same and systems for implementing the same.

A hybrid crosslinked polymeric membrane and a process for fabricating the same are provided. Specifically, the hybrid crosslinked polymer membrane comprises a glassy polymer and a ladder-structured polysilsesquioxane and has a crosslinked structure. The hybrid crosslinked polymer membrane can have an excellent permeability of carbon dioxide by virtue of an increase in the free volume and enhanced plasticization resistance, chemical resistance, and durability.

A low cost, sandwich-structured thin film composite (TFC) anion exchange membrane for redox flow batteries, fuel cells, electrolysis, and other electrochemical reaction applications is described. The sandwich-structured TFC anion exchange membrane comprises a microporous substrate membrane, a first hydrophilic ionomeric polymer coating layer on the surface of the microporous substrate layer, a cross-linked protonated polyamine anion exchange polymer coating layer on top of the first hydrophilic ionomeric polymer coating layer, and a second hydrophilic ionomeric polymer protective layer on top of the cross-linked protonated polyamine anion exchange polymer coating layer. Methods of making the TFC anion exchange membrane comprises a microporous substrate membrane and redox flow battery system incorporating the TFC anion exchange membrane comprises a microporous substrate membrane are also described.

A method for manufacturing a composite semipermeable membrane is capable of forming, on a surface of a porous support in a highly reproducible manner, a separation layer that is extremely thin and that exhibits superior separability. It provides, on a surface of a porous support, a composite semipermeable membrane that has an organic/inorganic hybrid separation layer that is extremely thin and that exhibits superior separability. A method for manufacturing a composite semipermeable membrane includes forming, on a surface of a porous support, a separation layer containing a cross-linked condensate having a siloxane bond by bringing an organic solution that contains an organic silicon compound containing three or more reactive functional groups, each of which is at least one type selected from a hydrolyzable group and a hydroxyl group, into contact with water or an aqueous solution on the porous support, and by performing interfacial polycondensation of the organic silicon compound.

The present invention relates to highly selective ultrathin polymer nanofilm; its composite membrane; its method of preparation. Composite membranes are produced via interfacial polymerization with addition of surface active reagents (SLS) to aqueous phase of piperazine amine and reacted with trimesoyl chloride. Fabricated ultrathin polymer nanofilm composite membrane gives high water permeance in range of 47.9-59.6 Lm.sup.−2h.sup.−1bar.sup.−1 with high rejection of Na.sub.2SO.sub.4 (91.77-98.47%); low rejection of MgCl.sub.2 (3.2-10.0%); NaCl (8.9-15.3%); high water permeance in range of 8.1-16.4 Lm.sup.−2h.sup.−1bar.sup.−1 with high rejection of Na.sub.2SO.sub.4 (99.81-99.99%); high rejection of MgCl.sub.2 (96.7-98.4%); NaCl (42.1-56.9%) when tested under 5 bar applied pressure at 25 (±1)° C. with 2 gL.sup.−1 feed. Ideal salt selectivity for NaCl/Na.sub.2SO.sub.4 is in range of 296.3-4310.

Water permeable membranes and methods of preparation are described. The water permeable membrane can comprise a porous support, and a polyamide layer comprising a crosslinked polyamide on a surface of the porous support, wherein the polyamide layer further comprises nanoparticles and a hydrophilic additive, and wherein the hydrophilic additive covalently bonds to the crosslinked polyamide. The crosslinked polyamide can be interfacially polymerized on the porous support. Methods for desalinating water, performing dialysis, or performing pervaporation using the water permeable membranes are disclosed.

Provided are composite articles having a membrane and a porous substrate, where the porous substrate has the membrane disposed thereon. The membrane has two layers, where the first layer has the second layer disposed thereon, and each layer has a plurality of polymer chains with a plurality of silicon-oxygen groups and a plurality of silicon-carbon groups. The first layer has a silicon to oxygen ratio of about 4:1 to about 1:1.25 and a silicon to carbon ratio of about 1:2 to about 1:10, and the second layer has a silicon to oxygen ratio of about 1:1 to about 1:2 and a silicon to carbon ratio of about 2:1 to about 10:1. At least a portion of the polymer chains of the second layer am crosslinked. The composite articles may be used in gas separation methods. Also provided are methods of making the composite articles and devices utilizing the composite articles.

A method for preparation of conductive polymer/carbon nanotube (CNT) composite nanofiltration (NF) membrane and the use thereof. This conductive polymer/CNT composite NF membrane is obtained by polymerizing conductive polymer into a CNT membrane and then in-situ cross-linking with glutaraldehyde under acidic condition. The synthetic method for the conductive polymer/CNT composite NF membrane is simple and has no need of expensive equipment. The prepared membrane has controllable membrane structure and possesses superior electrical conductivity and electrochemical stability. The membrane can couple with electrochemistry for electrically assisted filtration. With the electrical assistance, the membrane can achieve improved ion rejection performance while retaining high permeability by enhancement of membrane surface charge density, which alleviates the permeability-selectivity trade-off. Furthermore, the electrically assisted NF membrane filtration can also enhance the removal for small molecular organic pollutants.

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.