Description:
The outstanding removal performances of heavy metal ions are inseparable from a) the sufficient contact probability between heavy metal ions and adsorbent, b) convenient diffusion/accessibility of heavy metal ions on the surface and inside adsorbent, and c) abundant binding sites for heavy metal ions on adsorbent. Herein, we designed an efficient adsorbent of MnFe2O4MIL-53@UiO-66@MnO2 for Pb(II) and Cd(II) removal based on merging the self-propelled nanomotor, hierarchical structure and composite metal-organic frameworks (MOFs) to meet the above three requirements at the same time. The sufficient contact probability between Pb(II)/Cd(II) and MnFe2O4@MIL-53@UiO-66@MnO2 was achieved via self-propelled movement of the nanomotor induced by the catalytic decomposition of H2O2 by MnO2. The convenient diffusion/accessibility of Pb(II)/Cd(II) on the surface and inside MnFe2O4@MIL-53@UiO-66@MnO2 was realized by a hierarchical structured adsorbent constructed from different sophisticated complexing materials (MnFe2O4, MIL-53, UiO-66 and MnO2) with different pore sizes. Abundant binding sites (-COOH) from organic linker of MIL-53 and UiO-66 composite were provided for Pb(II)/Cd(II) ions to bind with the adsorbent. Besides, the complex of MnFe2O4 and MIL-53 endows the adsorbent with easy-recyclable property under an extra magnet. The nanomotor owns gratifying removal performances for Pb(II) and Cd(II) with excellent adsorption capacities and rapid removal rates