Solvothermal synthesis of nanoflakes-assembled hierarchical ZnWO4 microspheres as highly-efficient adsorbents for Pb2+ removal

Abstract

The simple synthesis of adsorbents with excellent efficiency is highly desirable, especially in removing heavy metal ions in wastewater. Herein, via an ethylene glycol (EG)-assisted solvothermal route, well-dispersed nanoflakes-assembled 3D hierarchical ZnWO4 microspheres have been prepared and evaluated as the adsorbents for the removal of Pb2+. The reaction time played vital roles in the morphological evolution process from nanoflakes to hierarchical microspheres. By taking advantage of the unique hierarchical structures, the electrostatic adsorption and larger specific surface areas (101.26 m2/g), a high adsorption efficiency for Pb2+ is achieved (up to 100% within 5 min at 100 mg/L) and the maximum adsorption capacity is 403.23 mg/g. The present work will open a new avenue to design adsorbents with high capacity and greatly expand the applications of ZnWO4 micro/nanomaterials for heavy metal ions removal.