Electrochemical‐Mediated Regenerable FeII Active Sites for Efficient Uranium Extraction at Ultra‐Low Cell Voltage.

Nano‐reduced iron (NRI) is a promising uranium adsorbent due to its strong reducibility and good selectivity, but it still faces the challenges of slow kinetics, limited and non‐renewable active sites. In this work, we realized high efficiency uranium extraction under ultra‐low cell voltage (−0.1 V) in seawater with 20 ppm UO2(NO3)2 solution by coupling electrochemical mediated FeII/FeIII redox and uranium extraction. The adsorption capacity and extraction efficiency of NRI after electrochemical uranium extraction (EUE) could reach 452 mg/g and 99.1 %, respectively. Combined with quasi‐operando/operando characterization technologies, we clarified the mechanism of EUE and revealed that continuously regenerating FeII active sites by electroreduction could significantly enhance the property of EUE. This work here provides a new electrochemical mediated and low energy consumption uranium extraction strategy which also provides a reference for other metal resource recovery. [ABSTRACT FROM AUTHOR]