Three-dimensional MgSiO3-coated SnO2/C nanostructures for efficient adsorption of heavy metal ions from aqueous solution

Abstract

Removal of heavy metal ions from aqueous solution for water purification through nanoadsorbents has been of great interest. However, the removal capacity and efficiency are still non-ideal due to some issues such as the agglomeration among adsorbents which severely reduces the adsorption sites. We present a potential strategy for developing adsorbents through surface modification on a specific three-dimensional (3D) nanostructure for adsorbing Pb(II) and As(V). A 3D hierarchical nanostructure which consists of a coral-like SnO₂/C base and a dense MgSiO₃ nanoflake coating on the surface was prepared through a two-step hydrothermal route. The 3D MgSiO₃-coated SnO₂/C nanostructure exhibits maximum adsorption capacities of about 185 and 109 mg g⁻¹ to Pb(II) and As(V), respectively. Impressively, the MgSiO₃-coated SnO₂/C has a higher removal efficiency than the SnO₂/C without MgSiO₃ coating, MgSiO₃ nanostructure, and the commercial active carbon. Good chemical and mechanical stability of the presented nanostructure is also confirmed by the characterization of the post-adsorbing adsorbents. In addition, a common stick coated with the presented nanoadsorbents was proposed and preliminarily used for heavy metal ion adsorption, exhibiting a promisingly simple method for water purification.