Abstract: Provided are a concentration method and system for concentrating a raw material solution, and in which a raw material solution containing a solute and a solvent is concentrated to obtain a concentrate of the raw material solution, wherein the solvent contains water and an organic solvent. In the method and system for concentrating a raw material solution, the system includes a combination of: a first concentrating means for removing water in the raw material solution by means of a forward osmosis method; and a second concentrating means for evaporating and removing water and an organic solvent in the raw material solution.

Abstract: This forward-osmosis composite hollow fiber membrane module has hollow fiber bundles, wherein: the hollow fibers are each such that a separation active layer of a high-molecular polymer thin film is provided on the inner surface of a macroporous hollow fiber support film formed from a high-molecular polymer including polyketone; the film surface area of the hollow fiber bundles is 100 cm2 or greater; and the coefficient of variation of the average thickness of the separation active layer in the radial and thickness directions of the hollow fiber bundle is 0-60%, said coefficient being calculated through a method for measuring the mass of the separation active layer portion in a scanning electron microscope image in which a thickness-direction cross section of the separation active layer is imaged.

Abstract: An asymmetric gas separation membrane made of an aromatic polyimide mainly containing repeating units having an ether bond which is heated at a temperature near a softening point (Ts) of the aromatic polyimide, and a method for separating methanol from a methanol-containing mixed organic vapor by allowing methanol to selectively permeate the asymmetric gas separation membrane using the membrane.

Abstract: An asymmetric gas separation membrane made of an aromatic polyimide mainly containing repeating units having an ether bond which is heated at a temperature near a softening point (Ts) of the aromatic polyimide, and a method for separating methanol from a methanol-containing mixed organic vapor by allowing methanol to selectively permeate the asymmetric gas separation membrane using the membrane.