Synthesis of silica nanoparticles from sodium silicate under alkaline conditions

Compared to the synthesis of silica nanoparticles from tetraethyl orthosilicate, its synthesis from sodium silicate solution (SSS) in alkaline medium is less investigated. Herein, we present a study for the synthesis of non-agglomerated silica nanoparticles from SSS under alkaline conditions. SSS was diluted with water and slowly added in the mixture of ethanol and ammonia to form a sol which was aged and centrifuged to obtain silica nanoparticles. Effect of different ratios of ethanol and ammonia in the mixture on the size of silica nanoparticles was studied, and these nanoparticles were characterized using scanning electron microscopy, Fourier transformation infrared spectroscopy and X-ray diffraction techniques. It was found that the produced silica nanoparticles were spherical in shape, non-agglomerated in nature and their size could be tailored with the change in the ratio of ammonia and ethanol.