Feasible design of 1D hierarchical Fe3O4@SiO2@PDA@MnO2 nanochains with high capacity for removal of organic pollutants

Abstract

One dimensional (1D) hierarchical nanostructures with large void spaces, high specific surfaces and multiple active site areas are of great interest for adsorption. Herein, 1D Fe₃O₄@SiO₂@PDA@MnO₂ nanochains with a hierarchical structure are fabricated by one-step magnetic assembly of Fe₃O₄@SiO₂@PDA nanochains, followed by coating with MnO₂ nanosheets (NSs) through an in situ redox reaction between PDA and KMnO₄ without using any extra reductant. During the synthetic process, the density of the MnO₂ NSs can be effectively tuned by introducing different dosages of KMnO₄. Owing to its unique hierarchical structure and high specific surface area, the as-prepared 1D magnetic composites are effective for the removal of methylene blue (MB). More importantly, the Fe₃O₄@SiO₂@PDA@MnO₂ nanochains can be easily collected from the solution. The adsorption results demonstrate that the Fe₃O₄@SiO₂@PDA@MnO₂ composites can be considered superior adsorbents for the removal of MB. This strategy also paves the way for the synthesis of 1D hierarchical adsorbents, which is of significant importance for real applications in environmental pollution.