Synthesis of water-soluble magnetic graphene nanocomposites for recyclable removal of heavy metal ions

Abstract

In this work, graphene oxide/Fe₃O₄ (GO/Fe₃O₄) composites were synthesized via a copper catalyzed azide-alkyne cycloaddition reaction for the first time. After further modification with polyacrylic acid (PAA), water-soluble magnetic graphene nanocomposites were obtained. The PAA/GO/Fe₃O₄nanocomposites were characterized by atomic force microscopy, transmission electron microscopy, X-ray diffraction, Raman, Fourier transform infrared spectroscopy, thermogravimetric analysis and vibrating sample magnetometry. Due to the high surface area, excellent complex ability and superparamagnetism, the PAA/GO/Fe₃O₄ nanocomposites were used as nanoadsorbents for recyclable removal of Cu²⁺, Cd²⁺ and Pb²⁺ ions from aqueous solution. It is found that the PAA/GO/Fe₃O₄ nanocomposites show extraordinary removal capacity for Cu²⁺, Cd²⁺ and Pb²⁺ ions. Moreover, the PAA/GO/Fe₃O₄ nanocomposites are very easy to separate and recycle due to the superparamagnetism of Fe₃O₄. After five cycles, the removal efficacy of the nanoadsorbents for Cu²⁺, Cd²⁺ and Pb²⁺ ions is over 85%. All of the results demonstrate that the water-soluble magnetic graphene composites are effective adsorbents for removal of heavy metals and thus could provide a new platform for water cleanup.