Abstract
Dry rice hulls contain 71-87 wt% organic matter such as cellulose and lignin and 13-29 wt% inorganic matter such as SiO2 and K2O depending on the species, climate and geographic location. The inorganic matter is composed of SiO2 (87-97 wt%) with small amount of alkali and other trace elements. The SiO2 in the rice hull was localized in the outer and inner epidermis of rice hull. The silica coexists with organic matter and the distance between SiO2 and organic matter is close conjunctively. Activated carbon with specific surface area of 3270m2/g was produced by the removal of SiO2 by the reaction of coked rice hulls prepared at 700˚C for 1 h in flowing N2 with KOH.
