New hierarchical zinc silicate nanostructures and their application in lead ion adsorption

Abstract

A low cost and reliable hydrothermal method was developed for the tunable synthesis of flower-like and urchin-like zinc silicate nanostructures. High resolution TEM, XRD, solid state ²⁹Si NMR spectra and X-ray nanotomography revealed new morphologies and crystal structures. Solid state NMR indicated very different silicon bonding patterns between the two materials. For urchin-like zinc silicates, a synchrotron based three dimensional X-ray nanotomography technique provided unprecedented structural details and revealed structural defects during the assembly process. For flower-like zinc silicates, HRTEM images showed that their secondary nanopetals had a clay-like layered structure, resulting in a higher BET surface area of 236 m² g⁻¹ as well as higher adsorption capacity for lead ions at 210 mg g⁻¹ than reported zinc silicate samples. The adsorption isotherms and mechanism were investigated.