Magnesium Silicate Hollow Nanostructures as Highly Efficient Absorbents for Toxic Metal Ions

A general one-step route has been developed for the selective synthesis of magnesium silicate hollow spheres, core−shell spheres, and nanotubes. The formation mechanism was studied. The concentration of NaOH played an important role in the synthesis of hollow and core−shell spheres, while the addition of glycol played a critical role in the synthesis of silicate nanotubes. These nanostructures usually have BET surface areas of 200−400 m 2 /g. Further investigation of their ion exchange performance shows that they are indeed perfect candidates as absorbents for heavy metal ions including Pb 2+, Cr 3+, Cd 2+, etc.