A facile procedure for the synthesis of δ-Na2Si2O5 using rice husk ash as silicon source

delta-Na2Si2O5, a potential builder in detergents, was prepared from rice husk ash by a simple sintering at 720 degrees C for 120 mm. The sample was characterized by X-ray diffraction (XRD), Raman spectroscopy (Raman), differential thermal analysis (DTA), thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscope (TEM), and EDTA titration. The XRD pattern confirmed the crystallization of delta-Na2Si2O5 obtained at 720 degrees C. The Raman shift at 552 cm(-1) and 1052 cm(-1) indicated the presence of a layered silicate tetrahedron structure in the sample. The loss of weight when the sample was heated from 120 degrees C to 516 degrees C in the TG curve was close to the theoretical weight loss calculated from the reaction formula and a broad exothermic peak at similar to 715 degrees C in the DTA curve demonstrated a phase transformation, consistent with previous reports. The SEM and TEM images indicated the typical structure of delta-Na2Si2O5 crystallization. The sample exhibited an excellent blinding capacity to Ca2+ and Mg2+; the optimal binding capacities were found to be 396 mg/g and 435 mg/g, respectively. (C) 2015 Elsevier B.V. All rights reserved.