Green graft process for preparation of functional mesoporous silica materials

Abstract

This study presents a green post-grafting method to prepare functional mesoporous silica materials. In the functionalisation stage, potassium iodide was applied as catalyst, and ecofriendly ethanol was used as solvent. The optimal molecular ratio of the reagent was n (potassium iodide)/n (3-chloropropyltriethoxysilane)/n (2-mercaptobenzothiazole) = 1·5∶1∶1·5. The reaction could be completed after reflux for 12 h at 90°C. The resulting materials were characterised by scanning electron microscopy, X-ray diffraction, nitrogen adsorption–desorption, Fourier transform infrared spectroscopy and elemental analysis. The results indicate that the large pore (the maximal size is ∼8·62 nm) functional mesoporous silica could be prepared by our improved graft method, which has a high efficiency of 50·63%. The functional mesoporous silica was applied to adsorb trace amount of heavy metal ions [Hg(II), Pb(II) and Cd(II)]. The materials exhibit large adsorption capacity and excellent regeneration ability.