Preparation of SiO2 aerogel from rice husk ash

摘要

Silica was leached from rice husk ash as sodium silicate by NaOH treatment. Using water glass as the silica source, SiO2 aerogel was prepared via the sol-gel process and supercritical drying of ethanol. Based on gelation time and porous characteristics of SiO2 aerogel, the optimum gel preparation technology was determined such as silica concentration of 6.0 wt%, gelation at pH value of 5.0 and aging in H2O/EtOH. Incidentally, the density was as low as 0.0713 g cm(-3), specific surface area was 729.82 m(2) g(-1), hole size was 3.39 cm(3) g(-1), and average pore size was 16.32 nm, and the size distribution was uniform.