METHOD FOR RECOVERING ACID

摘要

PROBLEM TO BE SOLVED: To prevent deterioration in electrolysis performance caused by membrane contamination owing to organic matter upon acid recovery from an acid solution by electrolysis.SOLUTION: In the method for recovering acid by electrolysis using a cation-exchange membrane and an anion-exchange membrane, a cation-exchange membrane is used. The cation-exchange membrane includes a vinyl alcohol-based copolymer having an anionic polymer segment which has an anionic group and a vinyl alcohol copolymer having a vinyl alcohol polymer segment, and has a micro phase separation structure in which domain size (X) lies in the range of 0 nm