A method for making a graphene oxide membrane and a resulting free-standing graphene oxide membrane that provides desired qualities of water permeability and selectivity at larger sizes, thinner cross sections, and with increased ruggedness as compared to existing membranes and processes.

Provided herein are ion-selective separation membranes including a polymer matrix and a metal compound dispersed within the polymer matrix. The metal compound includes H.sub.aLi.sub.bX.sub.cO.sub.a, where a is from 1 to 1.5, b is from 0 to 0.1, c is from 1 to 2, d is from 4 to 4.5, and X includes manganese or titanium.

A composite polyamide reverse osmosis membrane comprising a polyamide layer; where the polyamide layer has a thickness in the range of 50-250 nm, and large open spaces (i.e., free volumes); where the open spaces are defined by a ratio of water flux, J.sub.w, (gfd) divided by the average surface roughness, Ra, (nm) of the polyamide layer; wherein the composite polyamide reverse osmosis membrane has the ratio of J.sub.w/Ra>0.35 gfd/nm when tested at 65 psi, using an aqueous solution containing 250 ppm of NaCl; and a microporous support with a thickness ranging from 100-150 m. The present invention also relates to processes of fabricating the composite polyamide reverse osmosis membrane.

A method for preparing a self-supporting composite nanofiltration membrane is provided. A porous graphene-based two-dimensional sheet material is prepared by taking amino graphene quantum dots as the main body and subjecting them to an interfacial polymerization reaction with polyacyl chloride, and then the porous graphene-based two-dimensional sheet material is encapsulated in-situ with polyamide by an in-situ encapsulating technology to prepare a self-supporting porous graphene/polyamide separation layer with excellent permeability and high selectivity.

The present invention provides an anion exchange membrane that has low electrical resistance when used in electrodialysis, is produced without an increase in cost, and is excellent in selective permeability to monovalent anions, and a method for producing the same. The anion exchange membrane has a tertiary amino group and a quaternary ammonium group as functional groups, such that an intensity ratio of the tertiary amino group to the quaternary ammonium group is 1.0 or more as measured by X-ray photoelectron spectroscopy on a surface of the anion exchange membrane having the tertiary amino group and the quaternary ammonium group as the functional groups.

The disclosed subject matter provides a filter that is modified by a polymer-carbon based nanomaterial nanocomposite intended to significantly enhance the performance of filtration, separation, and remediation of a broad variety of chemicals, heavy metal ions, organic matters, and living organisms. Polymeric materials, such as but not limited to poly-N-vinyl carbazole (PVK), are combined with (1) graphene (G) and/or graphene-like materials based nanomaterials and (2) graphene oxide (GO) chemically modified with a chelating agent such as but not limited to EDTA. The nanocomposite is homogenously deposited on the surface of the membrane.

A nanocomposite membrane including an -Al.sub.2O.sub.3 membrane support, a -Al.sub.2O.sub.3 intermediate layer that is 300-1200 nm thick and coats a surface of the membrane support, and a nanocomposite layer including SiO.sub.2 and Y.sub.2O.sub.3 that is 25-150 nm thick and coats a surface of the intermediate layer, wherein the nanocomposite layer is porous with an average largest radius micropore of 0.2-0.6 nm. A method of manufacturing the nanocomposite membrane, whereby the membrane support is coated with the -Al.sub.2O.sub.3, a silica source is hydrolyzed with a mixture of water, an alcohol solvent, and a Y source with a sol-gel technique to yield a Si/Y sol-gel, the membrane support is dip coated with the Si/Y sol-gel, and the nanocomposite membrane is calcined. A method of separating a mixture of gas, whereby the mixture of gas is introduced into a permeance cell and fed through the nanocomposite membrane.

A nanocomposite membrane including -Al.sub.2O.sub.3 membrane support, a -Al.sub.2O.sub.3 intermediate layer that is 300-1200 nm thick and coats a surface of the membrane support, and a nanocomposite layer including SiO.sub.2 and Y.sub.2O.sub.3 that is 25-150 nm thick and coats a surface of the intermediate layer, wherein the nanocomposite layer is porous with an average largest radius micropore of 0.2-0.6 nm. A method of manufacturing the nanocomposite membrane, whereby the membrane support is coated with the -Al.sub.2O.sub.3, a silica source is hydrolyzed with a mixture of water, an alcohol solvent, and a Y source with a sol-gel technique yield a Si/Y sol-gel, the membrane support is dip coated with the Si/Y sol-gel, and the nanocomposite membrane is calcined. A method of separating a mixture of gas, whereby the mixture of gas is introduced into a permeance cell and fed through the nanocomposite membrane.

A nanocomposite membrane including an -Al.sub.2O.sub.3 membrane support, a -Al.sub.2O.sub.3 intermediate layer that is 300-1200 nm thick and coats a surface of the membrane support, and a nanocomposite layer including SiO.sub.2 and Y.sub.2O.sub.3 that is 25-150 nm thick and coats a surface of the intermediate layer, wherein the nanocomposite layer is porous with an average largest radius micropore of 0.2-0.6 nm. A method of manufacturing the nanocomposite membrane, whereby the membrane support is coated with the -Al.sub.2O.sub.3, a silica source is hydrolyzed with a mixture of water, an alcohol solvent, and a Y source with a sol-gel technique to yield a Si/Y sol-gel, the membrane support is dip coated with the Si/Y sol-gel, and the nanocomposite membrane is calcined. A method of separating a mixture of gas, whereby the mixture of gas is introduced into a permeance cell and fed through the nanocomposite membrane.

A high-flux silicon carbide ceramic filter membrane and a preparation method thereof are provided. In the preparation method, a separation layer is directly coated at a time on the basis of a support, that is, after the support is sintered, the separation layer is directly coated and then sintered for carbon removal. In the present disclosure, a sintering process and a coating formula are optimized to prevent fine silicon carbide particles from entering micropores of a support due to capillary filtration and film formation during coating, such that a separation layer with an average pore size of 0.2 m or less can be directly coated on a silicon carbide support with an average pore size of 10 m or more, and fine silicon carbide particles can be effectively prevented from entering micropores of the support during the coating.