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 Fe-II/Fe-III 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 Fe-II 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.

Automated summary

In this study, high efficiency uranium extraction was achieved under ultra-low cell voltage (-0.1 V) in seawater with 20 ppm UO2(NO3)(2) solution by coupling electrochemical mediated Fe-II/Fe-III redox and uranium extraction. The adsorption capacity and extraction efficiency of NRI after electrochemical uranium extraction (EUE) reached 452 mg/g and 99.1 %, respectively. Quasi-operando/operando characterization technologies were used to clarify the mechanism of EUE and it was revealed that continuously regenerating Fe-II active sites by electroreduction significantly enhanced the property of EUE.