Provided herein are in situ methods for fabricating a mixed-matrix membrane or a mixed-matrix hollow fiber membrane for increasing formation of zeolitic imidazolate framework nanoparticles inside the mixed-matrix membrane. Generally, in the method a polyimide polymer coated onto at least one support is hydrolzed with a base and the poly(amic acid)-salt film formed thereby undergoes ion exchange with a metal ion, treatment of the formed poly(amic acid)-metal salt film with an organic linker to produce metal-organic framework nanoparticles in situ, and imidization of the treated poly(amic acid)-metal salt film produces a polyimide/metal-organic framework mixed-matrix membrane or a mixed-matrix hollow fiber membrane module. Also provided is the mixed-matrix membrane and the polymer mixed-matrix hollow fiber membrane module fabricated by the methods and methods for separating a binary gas mixture via the fabricated mixed-matrix membrane.

A method for making a graphene membrane includes applying a suspension of graphene platelets in a fluid onto a porous substrate, and applying a pressure differential to force the fluid through the substrate to yield a filtered fluid while retaining the graphene platelets on the substrate. The graphene platelets and the substrate form the graphene membrane.

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 Al—O 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.

The present invention relates to a CO.sub.2 selective gas separation membrane and a method for preparing the gas separation membrane and the use thereof. The CO.sub.2 selective gas separation membrane comprises a gas permeable or porous support layer; and at least one gas permeable polymer layer, which is surface modified with polymer chains having CO.sub.2 philic groups, wherein the gas permeable polymer layer has a spatially controlled distribution of the CO.sub.2 philic groups on the surface thereof. The method of preparing the CO.sub.2 selective gas separation membrane, comprises the steps of: depositing at least one gas permeable polymer layer on a porous or gas permeable support layer to form a dense membrane, and surface modifying the dense membrane with polymer chains having CO.sub.2 philic groups, to obtain spatially controlled distribution of the CO.sub.2 philic groups on the surface thereof.

The present invention relates to a method for producing a polyelectrolyte complex (PEC) membrane having a predetermined porosity via salt dilution induced phase separation, in which a liquid polymer solution (P) containing polyanions (A) and polycations (C) dissolved in an aqueous medium at an overcritical salt concentration is exposed to an aqueous medium.

A method for preparing a high-selectivity lithium-magnesium separation membrane includes: (1) preparing an aqueous phase mixture containing aqueous phase monomer, crown ethers or aza-macrocycles, acid acceptor, surfactant and water; (2) preparing an organic phase mixture containing organic phase monomer, and organic solvent that is incompatible with water; (3) contacting the supporting membrane with the aqueous phase mixture to obtain an aqueous phase monomer-adsorbed supporting membrane; (4) contacting the aqueous phase monomer-adsorbed supporting membrane with an organic phase mixture for an interfacial polymerization reaction; and (5) placing a nascent membrane obtained into a drying oven and heat-treating the membrane to obtain a lithium-magnesium separation membrane. The present method is simple in preparation process, mild in preparation conditions, easy to scale up, and easy to realize industrial production. The prepared high-selectivity lithium-magnesium separation membrane is large in permeation flux, high in lithium-magnesium selectivity and good in long-term operation stability.

This disclosure relates to membranes containing a polymer containing crown ether monomer units and a guest compound capable of binding thereto. This disclosure also relates to methods for making the membranes, and to methods for using the membranes for gas separation applications.

Disclosed is the preparation of composite membranes formed by a tailored selective chemical modification of an ultra-thin nanoporous surface layer of a semi-crystalline mesoporous poly (aryl ether ketone) membrane with graded density pore structure. The composite separation layer is synthesized in situ on the poly (aryl ether ketone) substrate surface and is covalently linked to the surface of the semi-crystalline mesoporous poly (aryl ether ketone) membrane. Hollow fiber configuration is the preferred embodiment of forming the functionalized the poly (aryl ether ketone) membranes. Composite poly (aryl ether ketone) membranes of the present invention are particularly useful for a broad range of fluid separation applications, including organic solvent ultrafiltration and nanofiltration to separate and recover active pharmaceutical ingredients.

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.

The separations membrane system includes a substrate, a microporous layer, and a selective layer. The microporous layer may be disposed over the substrate. The selective layer may be disposed over the microporous layer, thereby sandwiching the microporous layer between the selective layer and the substrate. The microporous layer includes a thermoplastic material. The selective layer includes a polyamide structure of 2,2-Dimethyl-1,3-propanediamine and/or 1,3,5-Benzenetricarbonyl chloride.