Coral-like hydroxy sodalite particles from rice husk ash as silica source

Coral-like hydroxy sodalite (HS) particles were prepared from rice husk ash as silica source in the presence of other aqueous-based precursor materials following a simple process under hydrothermal condition at 90 degrees C for 15 h. The particles obtained at 90 degrees C for different times (6, 10 and 15 h) were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). The HS crystals along with a small amount of zeolite A particles were observed at 90 degrees C/6 h while phase pure HS particles were obtained at 90 degrees C for 10 and 15 h. The characteristic vibration bands of the HS particles were confirmed by FTIR spectroscopy. FESEM images showed that the HS particles obtained at 90 degrees C/15 h were coral-like morphology which were formed through the self-assembly of the smaller particles generated at the initial stage of reaction (6 and 10 h) under the same experimental conditions. A proposed mechanism for the formation of coral-like HS particles was also illustrated. (C) 2011 Elsevier B.V. All rights reserved.