Efficient capture of uranium by polydopamine functionalized MgO@Bi2O3 composite from aqueous solution

A series of polydopamine (PDA) modified MgO@Bi 2 O 3 composites (MB/PDA) with different mass ratios were fabricated to remove soluble U(VI). Batch experiments showed that MB/PDA-2 was provided with better adsorption performance than MB/PDA-1 and MB/PDA-3 and the maximum adsorption amount (C 0  = 10 mg/L, m/v = 0.1 g/L, pH = 4.0 and T = 298 K) reached 465.8 mg/g within 80 min. Moreover, over 95% U(VI) was removed by MB/PDA-2 in the process of dynamic adsorption and MB/PDA-2 still displayed high adsorption percentage (75%) after five cycles. The electrostatic attraction, complexation, redox reaction and cation-π interaction apparently influenced the U(VI) capture performance on MB/PDA-2. In short, MB/PDA-2 with high adsorption capacity was a preeminent material to extract soluble U(VI).