▎ 摘　　要

NOVELTY - Cation exchange membrane comprises 55-65 pts. wt. cation exchange resin, 35-45 pts. wt. binder resin, and 0.5-8 pts. wt. reduced graphene oxide. USE - The cation exchange membrane is useful in electrodeionization device for ultrapure water production system (claimed). ADVANTAGE - The cation exchange membrane increases mechanical strength while maintaining ion exchange capacity, and electrodeionization device to which the cation exchange membrane is applied can produce ultrapure water with improved removal performance of weak ions such as boron. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for electrodeionization device, comprising an anode, cathode, and cation exchange membrane and an anion exchange membrane positioned between the anode and the cathode and arranged alternately with each other. A spacer is positioned between the cation exchange membrane and the anion exchange membrane and filled with an ion exchange resin. The cation exchange membrane is the cation exchange membrane.