Electrochemical softening using capacitive deionization (CDI) with zeolite modified carbon electrode (ZMCE)

Divalent ions such as calcium and magnesium ions are thought to cause hardness in water inducing scale problems in the pipelines of boilers and heat exchangers. Thus, water softening has gained wide interest in water treatment technology. Although zeolite particles have been widely used as a material for the removal of divalent ions, its low ion-exchange efficiency based on diffusion-dependent process has limited their applications in water softening. Herein, we report effective electrochemical softening using zeolite with capacitive deionization (CDI), which is a desalination technology with electrochemical ad/desorption in an electric double layer. The carbon electrode with zeolite (denoted as a zeolite modified carbon electrode (ZMCE)) was prepared by the slurry and pasting method with zeolite particles and carbon black. ZMCE exhibited a significantly enhanced efficiency in the remova…