Capacitive Deionization for Selective Separation and Resource Recovery of Heavy Metal

The remediation of heavy metal pollution urgently requires efficient, highly selective, and sustainable technologies. Capacitive deionization (CDI) is a promising technology for the targeted removal and resource recovery of heavy metals. This paper reviews recent advances in this field, explaining the synergistic mechanisms between the electric double layer and Faradaic reactions, as well as how physical sieving, chemical recognition, and operational parameters enhance selective capture. Energy consumption, stability, and selectivity of various CDI configurations are compared. Removal strategies are discussed based on the oxidation states and chemical properties of typical heavy metals. Finally, the key challenges in transiting from laboratory research to engineering applications and future development directions are identified. The aim is to establish knowledge spanning mechanisms and applications to facilitate the development of highly efficient and selective heavy metal recovery systems.