Synthesis and Some Physical Features of Silica Xerogels Derived by Sol-Gel Method

This paper is concerned about the synthesis of silica xerogel samples at different values of pH by using inexpensive silica precursor (Na2SiO3). The synthesized xerogels were tested for physical tests like Scanning Electron Microscopy (SEM), X-rays diffractions (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. The micrographs of the gel obtained at higher pH values of the precursor solution showed that the particles are glassy and shiny in appearance. In the X-rays diffractogram of the gel sample where 6 % sodium silicate was used displayed only a single peak at 2 = 74o which points towards the crystalline nature of the sample. However, the xerogel with 4 % of the silica precursor showed no peak except a broad peak centered at 2θ angle of 22° which confirmed its amorphous nature. The crystallinity was observed to be affected with the change in pH of the precursor during the gel fabrication.

Syed Rashid Saeed, Syed Sakhawat Shah, Muhammad Waseem, Wajid Rehman and Muhammad Siddique