A Low-cost Preparation of SiO$lt;inf$gt;2$lt;/inf$gt; Aerogel Monoliths from Silica Sol

Porous monolithic SiO 2 materials were prepared via ambient pressure drying process with low cost silica sol as precursor and water as solvent. Cetyl trimethyl ammonium bromide (CTAB) was used as the surface modifier to get rid of the cumbersome process of solvent substitution which was necessary in the traditional ambient drying process. The densities, specific surface area and the average pore size of the obtained SiO 2 monoliths are in the range of 150-260 mg/cm 3 , 91-140 m 2 /g and 15-27 nm, respectively. The thermal conductivity was as low as 0.048 W/(mK) at room temperature. This method greatly reduced the preparation cost as well as the operation difficulty and risk, which will largely promote the industrial production and application of porous SiO 2 materials.