Preparation and adsorption property of hydrophobic SiO2 aerogels modified by methyl triethoxysilane

Abstract

The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate(TEOS) as silica source, methyl triethoxysilane (MTMS) as modifier, ethanol as solvent. Moreover, the structure and adsorption property of SiO2 aerogels were also studied. As results, the surface area of SiO2 aerogels was 863.59 m2/g, the pore volume was 3.57 cm3/g, and the contact angle was 150°. Adsorption intensity of silica aerogels for organic liquid (alkanes, benzene compounds, and nitro-compounds) is bigger than that of activated carbon. The mass of the liquid absorbed increased linearly with the surface tension of the liquid. The lower surface tension and boiling point are, the shorter desorption time is. After regenerating 10 times, nitromethane regeneration rate remain the same, and almost more than 94%. So SiO2 aerogels have good absorption and regeneration property.