Described herein is a graphene material based membrane that provides selective resistance for solutes or gas while providing water permeability. A selectively permeable membrane comprising graphene oxide, reduced graphene oxide, and also functionalized or crosslinked between the graphene, that provides enhanced salt separation from water or gas permeability resistance, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

A method of preparing a graphene-based membrane is provided. The method may include providing a stacked arrangement of layers of a graphene-based material, wherein the layers of the graphene-based material define one or more nanochannels between neighboring layers, and varying an electrical charge on a surface of the layers of the graphene-based material defining the one or more nanochannels to control size selectivity and/or ionic selectivity of the graphene-based membrane. A graphene-based membrane and a method of separating ions from a fluid stream are also provided.

The invention relates to a catalytic activation layer for use in oxygen-permeable membranes, which can comprise at least one porous structure formed by interconnected ceramic oxide particles that conduct oxygen ions and electronic carriers, where the surface of said particles that is exposed to the pores is covered with nanoparticles made from a catalyst, the composition of which corresponds to the following formula:

A.sub.1-x-yB.sub.xC.sub.yO.sub.R where: A can be selected from Ti, Zr, Hf, lanthanide metals and combinations thereof; B and C are metals selected from Al, Ga, Y, Se, B, Nb, Ta, V, Mo, W, Re, Mn, Sn, Pr, Sm, Tb, Yb, Lu and combinations of same; and A must always be different from B. 0.01 <x<0.5; 0<y<0.3.

A method for preparing a film of aligned rod-like nanostructures or nanotubes comprises preparing a solution that comprises rod-like nanostructures or nanotubes, wherein the rod-like nanostructures or the nanotubes are well-dispersed, and performing vacuum filtration of the solution through a filtration membrane, wherein the vacuum filtration produces a film on the filtration membrane where the rod-like nanostructures or the nanotubes are aligned. The well-dispersed individual rod-like nanostructures or nanotubes may be separately suspended in the solution. The concentration of rod-like nanostructures or nanotubes may be below a threshold value and/or the filtration speed may be as slow as possible. Where a surfactant is utilized to aid dispersion, the surfactant concentration may be below a critical micelle concentration (CMC).

A membrane for fluid species transport includes a porous substrate and a selective-transport layer comprising 2-D-material flakes. The porous substrate defines surface pores with dimensions larger than 2 microns, and the selective-transport layer coats the porous substrate and spans across the surface pores. The porous substrate can be contacted with a liquid or coating to fill or coat the surface pores of the porous substrate. Next, a 2-D-material-flake solution is deposited on the porous substrate. Evaporation of solvent from the deposited 2-D-material-flake solution forms the selective-transport layer.

A separation membrane includes a membrane comprising a polymer, characterized in that a functional layer is formed on the surface in one side of the membrane, the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface of the preceding functional layer is 0.1% (by atomic number) or more but not more than 10 (% by atomic number), and the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface opposite to the functional layer is not more than 10 (% by atomic number). A separation membrane module suffering from little sticking of organic matters, proteins, platelets and so on is provided with the separation membrane as a built-in membrane.

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.

The present disclosure provides a rigid self-supporting MXene separation membrane and a preparation method and use thereof, belonging to the technical field of membranes. In the present disclosure, a MXene material is mixed with an aluminum salt powder to conduct one-step membrane formation by hot-pressing. The pressure forms the powder into a membrane and imparts rigidity, enabling a self-supporting structure; the heating breaks an ionic bond of an inorganic metal salt to reach a molten ionic state, and free metal cations react with active oxygen-containing functional groups on the surface of the MXene to form new chemical bonds (such as an AlO bond); such a chemical bond has higher energy, achieving a desirable anti-swelling effect to improve the membrane stability. The separation membrane further has excellent conductivity and hydrophilicity.

Embodiments described herein relate generally to graphene oxide membranes for fluid filtration and more specifically to graphene oxide membranes having tunable permeability, rejection rate, and flux. Some embodiments of the graphene oxide membranes disclosed herein are characterized as having a flux of at least about 2.510.sup.4 gallons per square foot per day per psi with a 1 wt % lactose solution at room temperature, and a lactose rejection rate of at least 50% with a 1 wt % lactose solution.

Filtration apparatus including Graphene Oxide (GO) are described herein. The GO membranes include a plurality of graphene oxide sheets, each of the graphene oxide sheets covalently bound to a chemical spacer. The filtration apparatus can include a GO membrane and a sulfonated polyethersulfone (S-PES). The filtration apparatus can exhibit improved performance with respect to prior art membranes (e.g., high flux and rejection rate) in applications such as pulp and paper processing, which facilitates achieving permeate quality targets. The filtration apparatus described herein can also offer a more stable replacement for reverse osmosis membranes which are known to degrade under strongly alkaline conditions and high temperatures.