A method for preparing a nanofiltration membrane and a nanofiltration membrane prepared therefrom, the method comprising the following steps: dissolving a polymer in a solvent to prepare a polymer solution, and curing the polymer solution on a support material to form a base membrane; sequentially applying a first liquid-phase solution and a second liquid-phase solution on the base membrane to form a nascent membrane; densifying the nascent membrane by using a solution that contains an alkaline substance; processing the densified nascent membrane by using a solution that contains an acidic substance; and obtaining the nanofiltration membrane after post-processing and drying.

The present disclosure relates to a method of preparing a thin film composite layer immobilizing vesicles incorporating a transmembrane protein on a porous substrate membrane, comprising providing an aqueous solution comprising the vesicles and a di-amine or tri-amine compound, covering the surface of a porous support membrane with the aqueous solution, applying a hydrophobic solution comprising an acyl halide compound, and allowing the aqueous solution and the hydrophobic solution to perform an interfacial polymerization reaction to form the thin film composite layer.

Novel membranes suitable for use in separation applications are described, as well as processes by which the membranes are made and uses of the membranes in a range of separation applications. The membranes are obtainable by an interfacial polymerisation reaction involving two monomers, in which at least one of the monomers comprises oligomeric portions that are suitable for tuning the separation characteristics of the membrane, particularly in liquid separations, such as organic solvent nanofiltration.

A composite semipermeable membrane 12 of the present invention includes a porous support membrane 12a and a skin layer 12b supported by the porous support membrane 12a. The membrane surface of the composite semipermeable membrane 12 has an elastic modulus of 250 MPa or more and 500 MPa or less as calculated by force curve measurement using AFM in water. A spiral membrane element 20 of the present invention includes the composite semipermeable membrane 12 of the present invention. A water treatment system 100 of the present invention includes the spiral membrane element 20 of the present invention.

The invention relates to methods for the synthesis of a thin-film composite membrane, comprising the following steps: a) providing an ultrafiltration porous support membrane, coated at the outer surface with a thin film, synthesized through interfacial polymerisation or interfacial initiation of polymerisation, b) contacting the membrane with a first solution comprising a first monomer, and allowing the solution to impregnate inside the thin film of the membrane, c) discarding the first solution comprising the first monomer, d) contacting the membrane with a second solution comprising a second monomer, and allowing the solution to impregnate inside the thin film of membrane, whereby the second monomer reacts with the first monomer and optionally with reactive groups of the thin film, e) discarding the second solution comprising the second monomer.

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.

An object of the present invention is to provide a composite reverse osmosis membrane having improved water permeability and antifouling performance, and a method for producing the same. The composite reverse osmosis membrane of the present invention includes: a porous support; and a skin layer formed on a surface of the porous support. The skin layer contains a polyamide resin. The polyamide resin is a modified polyamide resin modified with an alkylenediamine derivative.

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.

Provided is a composition for forming a separation membrane active layer, the composition comprising a compound of the following Chemical Formula 1 and a compound of the following Chemical Formula 2, wherein a percentage (a/b) of a weight (a) of the compound of Chemical Formula 1 to a weight (b) of the compound of Chemical Formula 2 is 30% to 60%, and a pH thereof is 11 to 12.7:

##STR00001## wherein in Chemical Formulae 1 and 2: R1 to R16 are each independently —CRR′— or —NR″—. at least two of R1 to R10 are —NR″—; at least two of R11 to R16 are —NR″—; and R, R′, and R″ are each independently hydrogen or a substituted or unsubstituted alkyl group; a method for producing a separation membrane; a separation membrane; and a water treatment module.

The purpose of the present invention is to provide: a composite semipermeable membrane which has three excellent properties, namely, excellent ionic substance rejecting property, excellent nonionic substance rejecting property and excellent water permeability in a practically balanced manner, and a spiral wound separation membrane element which comprises this composite semipermeable membrane. A composite semipermeable membrane according to the present invention is obtained by forming a skin layer that contains a polyamide-based resin on a surface of a porous support, and is configured such that: the polyamide-based resin is obtained by polymerizing a polyfunctional acid halide component and a polyfunctional amine component; the polyfunctional amine component contains m-phenylenediamine and at least one diamine compound represented by general formula (1); and a ratio (mol %) of a segment (A) derived from m-phenylenediamine and a segment (B) derived from the diamine compound in the polyamide-based resin is 99.9:0.1 to 98:2 (segment (A):segment (B)). ##STR00001##