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

ABSTRACT

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.