Synthesis of zeolite T powders by direct dissolution of rice husk ash: an agro-waste material

Abstract

Rice husk ash (RHA), an agro-waste material, was used for the synthesis of zeolite T powders following a simple and cost-effective process. In this process, silica as silicate was directly extracted from solid RHA particles in the presence of aluminate and other aqueous-based precursor materials. The synthesized powders were characterized by thermogravimetry analysis, differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, N2 physisorption measurements, and field emission scanning electron microscopy (FESEM). Crystallization of zeolite T powders was noticed at 100 °C/24 h. The vibration bands of the powders at around 580 and 630 cm−1 indicated the characteristic double six ring of zeolite T. Micropore surface area and micropore volume of zeolite T increased significantly at 100 °C/72 h. FESEM images showed ellipse-shaped morphology of the powders, and their aspect ratio increased with increase in reaction time. A tentative mechanism was proposed for direct extraction of silica as silicate from RHA, and its conversion to zeolite T in the presence of other aqueous-based precursors by a single step process.