Fe3O4/PANI/MnO2 core–shell hybrids as advanced adsorbents for heavy metal ions

Abstract

Multifunctional magnetic adsorbents containing MnO₂ and polyaniline (PANI) with optimized adsorption properties toward heavy metal ions have been developed. In particular, Fe₃O₄ spheres were chosen as the magnetic core, followed by PANI and MnO₂ coating, realizing the formation of Fe₃O₄/PANI/MnO₂ core–shell hybrids. The as-synthesized Fe₃O₄/PANI/MnO₂ core–shell hybrids showed a hierarchical structure with a large surface area and high magnetic saturation value. In comparison with Fe₃O₄/PANI and Fe₃O₄/MnO₂ core–shell hybrids, Fe₃O₄/PANI/MnO₂ core–shell hybrids displayed the highest adsorption capacity toward heavy metal ions (including Cd(II), Zn(II), Pb(II) and Cu(II)), thanks to the integrated physical and chemical adsorption behaviors resulting from MnO₂ inorganic oxide and the PANI polymer. The developed multifunctional Fe₃O₄/PANI/MnO₂ adsorbents synthesized by a facile and economic route are believed to show high potential in environmental remediation for heavy metal removal.