The recoverability of the extracted U on Ti electrode was evaluated. Both the physicochemical method and the electrochemical method were examined (see Supplementary Note 9 for details). As shown in Figure , by the physicochemical method, the 0.1 M HCl could recover 66.3% of the extracted U. By applying a bias voltage, the elution of the extracted U could be promoted. In the 0.1 M HCl elution solution, the U recovery rate was 83.2% at 1.0