Efficient electrosorption of uranium(VI) by B, N, and P co-doped porous carbon materials containing phosphate functional groups

In this paper, polyphosphazene was synthesized as precursors using benzene-1,4-diboronic acid and hexachlorocyclotriphosphazene (HCCP) by a simple one-step ultrasonic method. Furthermore, B, N, and P co-doped carbon materials containing phosphate functional groups (denoted as BNPCs-PO4) was obtained by the carbonization and functionalization of precursors at high temperature. Through the structural characterization and the investigation of electrochemical and electrosorption properties, it can be proved that BNPCs-PO4 has excellent porous structure and electrosorption properties with the maximum electrosorption capacity of 750 +/- 40 mg/g for U(VI) and the equilibrium time of 24 min. The optimal pH and applied potential for electrosorption were 5.0 and 0.9 V, respectively. Meanwhile, it also showed high selectivity under the coexistence of multiple metal ions and excellent recyclability after six cycles. The results showed the introduction of heteroatoms improved the electrosorption properties of carbon materials and BNPCs-PO4 can be utilized as electrode for the removal of U(VI) in aqueous solution.