Preparation of hydrophobic hollow silica nanospheres with porous shells and their application in pollutant removal

A series of hydrophobic hollow silica nanospheres with high specific surface areas and porous shells were successfully prepared through combination of a one-step reverse-phase microemulsion route and a simple post selective etching method. These materials owned porous shells and high specific surface areas, which were generated in the etching process. The distribution difference of organic groups among the solid nanosphere was innovatively utilized to create a different etching rate between the surface and the inner part of the solid silica nanosphere. After etching, the organic groups are still present on the surface which together with the rough surface give it hydrophobic properties and the contact angles can reach 150°. The reported materials showed good performance in the removal of 4-NP in water.