COMPOSITE SEMIPERMEABLE MEMBRANE AND METHOD OF PRODUCING THE SAME

摘要

Provided is a composite semipermeable membrane having a polyamide separation-functional layer on a porous support layer, wherein the polyamide separation-functional layer has a yellow index of 10 to 40, and the actual length of the polyamide separation-functional layer per 1 μm-length of the porous support layer is from 2 μm to 5 μm, or a composite semipermeable membrane having on a porous support layer a polyamide separation-functional layer prepared by polycondensation of polyfunctional amines with polyfunctional acid halides, wherein the polyamide separation-functional layer is formed by the steps of (A) interfacial polycondensation in which polyfunctional amines and polyfunctional acid halides are brought into contact at 40° C. to 70° C. and subsequent (B) heat treatment at 70° C. to 150° C. The composite semipermeable membrane according to the present invention has high boron removal performance and high water permeation performance.