A Facile Hydrothermal Conversion of Rice Husk Ash to ZSM-5 Zeolite Powders

The ZSM‐5 zeolite powders were prepared through in situ extraction (extraction and conversion in single step process) of silica from rice husk ash in the presence of other aqueous‐based precursors (sodium aluminate and tetrapropyl ammonium hydroxide) following a simple hydrothermal condition at 130°C–170°C. The powders were characterized by X‐ray diffraction (XRD), thermogravimetry analysis (TGA), differential thermal analysis (DTA), Fourier transform infrared (FTIR) spectroscopy, N2 physisorption measurements, and field emission scanning electron microscopy (FESEM). Crystallizations of ZSM‐5 were noticed at 130°C/96 h, 150°C/24 h, and 170°C/12 h. The exothermic peak at 422°C in DTA curve indicated the removal of tetrapropyl ammonium ions (TPA+) used as structure directing agent (SDA). The vibration bands at around 550 and 1221 cm−1 indicated the presence of double 5‐ring in ZSM‐5. The 150°C–170°C‐treated samples exhibited higher BET surface area and pore volume compared to those of 130°C‐treated powders. The FESEM images showed coffin‐shaped morphology of the powders, and their sizes increased with increase in both reaction temperature and time.