COMPOSITE SEMIPERMEABLE MEMBRANE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a composite semipermeable membrane having high solute removing property and high water permeability and capable of operating at high recovery. SOLUTION: The composite semipermeable membrane has a separation functional layer of a crosslinked polyamide formed on a porous supporting membrane by the polycondensation of a polyfunctional amine, a polyfunctional acid halide and a polyfunctional acid anhydride. Water permeability under 0.3 MPa operation pressure at 25 deg.C and pH 6.5 is controlled to be 0.8-4.0 m3/ m2.day and the removing rate of humic acid is controlled to >=98%.