Latest Progress on Synchronous Removal of Multiple Heavy Metal Cations and Anions: Adsorbent Design and Mechanism Elucidation

The development of highly efficient remediation technologies for heavy metal pollution has attracted widespread attention. Due to the "trade-off" effect arising from the different occurrence states and physical-chemical properties of heavy metal cations and anions in the different pH environments, the remediation of coexisting multiple heavy metal contamination is significantly complex and challenging. As such, the investigation of highly selective and efficient adsorbents for multiple heavy metals removal is the present focus of the scientific and industrial community. Under such circumstances, we report the latest progress on multiple heavy metals removal in this review. Firstly, we summarize the current situation of heavy metal contamination and the corresponding remediation methods. Secondly, we divide the discussion into three sections, including the heavy metal cation removal, heavy metal anion removal, and the coexisting multiple heavy metal removal from the perspective of removal mechanisms and the used adsorbents. Finally, we highlight the future challenges and opportunities in the development of promising adsorbents for multiple heavy metals removal.