Construction of an electrochemical reactor for efficient water softening via promoting CaCO3 nucleation in liquid phase

Abstract

In order to solve the problems of frequent electrode cleaning and low efficiency in electrochemical descaling, a new electrochemical water softening reactor with horizontal electrodes was developed. In the new electrochemical water softening reactor, the inflow flowed horizontally through the cathodic chamber and then the anodic chamber. The movement of water and bubbles promoted OH- diffusion and strengthened the homogeneous nucleation of CaCO3. By optimizing current density, flow rate and initial hardness, the homogeneous nucleation was strengthened. At the flow rate of 2.7 L/h, the current density of 80 A/m2 and the influent hardness of 400 mg/L, the softening efficiency was achieved as 155 g/(h·m2), hardness removal was 150 mg/L, current efficiency was 50% and energy consumption was 15 kW·h/g. With these performance, cathodic cleaning frequency was reduced effectively.

Keywords

• electrochemistry
• water softening
• oh- diffusion
• softener