A Study on Removal of Cobalt from a Primary Coolant by Continuous Electrodeionization with Various Conducting Spacers

Abstract

The production of high purity water in the primary coolant of a nuclear power plant was investigated using a CEDI process with three ion-conducting spacers, i.e., ion-exchange resin (IX), an immobilized ion-exchange polyurethane resin (IEPU), and an ion-exchange textile (IET). The spacers were characterized by varying experimental conditions, e.g., dosage of adsorbent, pH of the solution, contact time, and the porous-plug model. The CEDI stack was assembled as a bed layered with the cation-exchange and anion-exchange materials. The stack configuration was designed to prevent a reaction between the metal ions and hydroxide ions. The performance of the CEDI operation with the layered bed showed more than 99% removal of the ions at a current efficiency ranged from 18 to 24%. In this study, the feasibility of using the CEDI in operations for the removal of heavy metals present at very low concentrations was successfully demonstrated.