Abstract: This invention relates to a multi-element membrane separator and separation method based on spiral-wound membrane elements. It includes a membrane housing, spiral-wound membrane elements, and baffles on both sides of the membrane housing, designed to secure the spiral-wound membrane elements. The permeate tubes of the spiral-wound membrane elements are connected to the openings in the perforated plates. Sealing rings are respectively provided at the connections of the permeate tubes and the perforated plate openings. This multi-element membrane separator enables a more compact arrangement of membrane elements, reducing the footprint of the membrane separation device. It also reduces the use of materials such as membrane housing, pipelines, and connecting fittings, thereby lowering equipment costs and the difficulty of membrane device assembly.

Abstract: 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.