A novel four-chamber flow electrode capacitive deionization system for continuous recovery of heavy metal ions from wastewater

In view of the pollution of heavy metals to the environment and the importance for the industrial production, the removal and recovery of heavy metals from various water system is of great importance. In this study, a novel four-chamber flow electrode capacitive deionization (F-FCDI) process is constructed and successfully applied to the removal and recovery of heavy metal ions. Compared with conventional flow electrode capacitive deion-ization (FCDI) system, the F-FCDI system exhibits higher salt removal efficiency, faster salt removal rate, and lower energy consumption. The effect of different operating parameters on the removal efficiency of copper ions by F-FCDI system is studied, including the initial metal ions concentrations, the applied voltage, and the acti-vated carbon content. The enrichment performance of the constructed F-FCDI system was evaluated under the optimal conditions (applied voltage 1.2 V, 5 wt% activated carbon content). 2000 mL Cu2+ solution with initial concentration 100 ppm was recycled in the F-FCDI system for 48 h and successfully enriched to 50 mL of concentrate solution. The enrichment factors reached 28.5 times, and the removal and enrichment of Cu2+ were realized synchronously. The removal efficiency of some other metal ions, like Ca2+, Mg2+, Pb2+, Cd2+, Co2+ was also evaluated. The removal efficiency can also reach more than 90% in F-FCDI system (initial concentrations 100 ppm). This study provides reference value for the removal and recovery of heavy metal ions in the future.