Extraction and Physicochemical Characterization of Highly-pure Amorphous Silica Nanoparticles from Locally Available Dunes Sand

Abstract

This study synthesized highly pure silica nanoparticles from the northeast Algerian Sahara dunes sand as a low-cost silica source using a simple and environmentally friendly method. The silica nanoparticles were extracted using a sodium silicate solution as a precursor without employing any additive agents. The extracted silica’s crystalline structure, chemical composition, chemical bonding, microstructure, elemental analysis, thermal analysis, and optical characteristics were investigated. The X-ray diffraction patterns demonstrate the amorphous nature of the extracted silica. Furthermore, the X-ray fluorescence spectroscopy (XRF) and energy dispersive X-ray (EDX) results prove the high purity of the extracted silica (99% SiO2). However, the Fourier-transform infrared spectroscopy (FTIR) results corroborate the presence of silanol and siloxane groups. According to the SEM image analysis, the produced silica has an average particle size in the range of nanometers. Thermal analysis (TGA/DTA) exhibited the high thermal stability of the silica, and the optical band gap energy for silica nanoparticles was determined to be 3.75 eV. Therefore, dunes sand is an alternative source for developing high-purity silica nanoparticles, which have great potential for advanced material applications.