Synthesis and Characterization of Nano Silica from Local Siliceous Sand

A commercial silica (SiO2) powder was synthesized using a chemical reaction. The method of preparing silica nanoparticles from siliceous sand comprises: grinding the siliceous sand; solving siliceous sand with sodium hydroxide to form sodium silicate aqueous solution; neutralizing an aqueous solution of sodium silicate with hydrochloric acid to form precipitate; washing to remove chlorine; drying the nano silica and grind the nano silica powder. Furthermore, the nano silica surface was treated with surfactant hexamethyldisilazane (HMDS). The yield for different reaction time of siliceous sand with sodium hydroxide was calculated. Moreover, the structure, particle size distribution and morphology were determined by Fourier Transform Infrared Spectrometry (FTIR), Particle Size Analyzer, Scanning Electron Microscopy (SEM) and X-Ray Distribution (XRD). The result showed that the yield of sodium silicate solution is higher with the present of glycerol (more than 80%) and increasing with reaction time. SEM results show that nano silica is agglomeration form with the dimension of 96 nm. However, after treated with HMDS, the nano silica forms less agglomerate with average size of 88 nm. The FTIR spectrum confirms that the HMDS modifier is incorporated on the surface of SiO2 particles. XRD pattern of nano silica confirms the amorphous nature of the nano silica compared before synthesis which is in crystal structures.