Shape evolution and applications in water purification: The case of CVD-grown Zn ₂SiO ₄ straw-bundles

3-D straw-bundle-like Zn ₂SiO ₄ architectures assembled from numerous radial nanowires were synthesized by a simple thermal evaporation method using ZnCl ₂ powder as reactant. The growth process was studied in detail and a "nanorods-to-straw-bundles-to-spheres" mechanism was proposed for the nanostructures synthesized from the vapor process. The application of the Zn ₂SiO ₄ straw bundles for the removal of toxic metal ions in water, Fe ^III and Cd ^II in this case, was investigated and the results indicate that the amount of Fe ^III and Cd ^II adsorbed onto the surface of the Zn ₂SiO ₄ straw bundles increased with the increase of pH values, and the Zn ₂SiO ₄ nanostructures showed better removal capacity for Fe ^III ions than Cd ^II ions.