In-situ reduction synthesis of manganese dioxide@polypyrrole core/shell nanomaterial for highly efficient enrichment of U(VI) and Eu(III)

Radionuclides with long half-life are toxic, and thereby result in serious threat to human beings and ecological balance. Herein, a simple two-step synthesis method was used to prepare manganese dioxide@polypyrrole (MnO2@PPy) core/shell structures for efficient removal of U(VI) and Eu(III) from aqueous solutions. The adsorption of U(VI) and Eu(III) were investigated under different kinds of experimental conditions. The experimental results suggested that the adsorption of U(VI) and Eu(III) on MnO2@PPy were greatly affected by pH. U(VI) adsorption on MnO2@PPy was independent of ionic strength at pH < 6.0, and dependent on ionic strength at pH > 6.0. However, Eu(III) adsorption on MnO2@PPy was independent of ionic strength at the whole pH range of experimental conditions. The maximum adsorption capacities (q (max)) of U(VI) and Eu(III) were 63.04 and 54.74 mg g(-1) at T=298 K, respectively. The BET, XRD, FTIR and XPS analysis evidenced that high adsorption capacities of U (VI) and Eu(III) on MnO2@PPy were mainly due to high surface area and rich metal oxygen-containing group (i.e., Mn-OH and Mn-O), and the interaction was mainly attributed to strong surface complexation and electrostatic interaction. This study highlighted the excellent adsorption performance of U(VI) and Eu(III) on MnO2@PPy and could provide the reference for the elimination of radionuclides in real wastewater management.