Preparation and characterization of nano-porous silica aerogel from rice husk ash by drying at atmospheric pressure

Silica aerogel, a mesoporous material, was prepared from rice husk ash by sol–gel method and dried under atmospheric pressure. In this method, rice husk ash, which is rich in silica, was extracted with sodium hydroxide solution to produce a sodium silicate solution. This solution was neutralized with acid to form a silica hydrosol, and a small amount of tetraethyl silicate (TEOS) to form a gel. The aged gel was washed carefully by distilled water and ethanol and finally dried under atmospheric air. The prepared silica aerogels were characterized by XRF, FT-IR, TG, DTA, DTG, XRD, BET and SEM measurements. The synthesized TEOS-doped silica aerogel was a light solid with specific surface area of 315 m2/g, pore volume 0.78 cm3/g, average pore size 9.8 nm, bulk density 0.32 g/cm3 and porosity 85%.

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► The cheap method for preparation silica aerogel from rice husk.
► Porosity as high as 85%.
► Average pore diameter of 0.7771 nm, surface area 315.64 m2/g and pore volume 3.89 cm3/g.