The spectrum confirms that silica from cogon grass contains pure
silica as evidenced from the large absorption between 800 and
1200 cm−1. In addition, a small peak was observed at 1650 cm−1,
which is caused by absorbed water. Compared with the silica obtained
from RHA and rice straw, cogon grass silica exhibits less absorption of
silanol groups. Therefore, the silica powder from cogon grass is confirmed
to have different surface characteristics than RHA and rice straw