PURPOSE: To obtain a composite membrane excellent in oxidation resistance and selectivity for separation and having a high water permeability, by a method wherein an ultra-thin film, prepared by cross-linking polymerization of a specified amino compound monomer, and a porous inside layer prepared by making a polycarboxylic acid water-insoluble are supported on a porous substrate.
CONSTITUTION: An aqueous solution containing a polyacrylic acid, piperazine and NaOH is coated uniformly on a porous substrate made of a polysulfone. Then, the substrate is immersed in an n-hexane solution of trimesoyl chloride used as a polyfunctional cross-linking agent. After taking out the substrate from the n-hexane solution and evaporating off the n-hexane adhered on the membrane surfaces, the membrane is heat-treated.
YOSHIOKA NORIAKI
NAKAGOME KEISUKE
