Silica xerogel and iron doped silica xerogel synthesis in presence of drying control chemical additives

Abstract

Silica xerogels were prepared by sol-gel method in presence of glycerol and oxalic acid as drying control chemical additivites (DCCAs). They were characterized with TGA, XRD, TEM, nitrogen adsorption/desorption isotherm, XPS, ICP, FTIR and UV–vis DR analyses. TGA results showed that the use of DCCAs provided a controlled release of water, thereby preventing structure collapse which was supported by nitrogen adsorption technique. DCCAs caused an increase in microporosity of xerogels, while some decreases in surface area and total pore volume values were occurred. Amorphous silica structure and silica density decreasing effect of DCCAs were observed from XRD patterns. While XPS, XRD and UV–vis DR analyses showed the presence of iron species in Fe2O3 form, they were found to settle as nanoparticles from TEM images. ICP results showed that iron incorporated to the xerogel structure as percent of 83. Iron loading caused significant increases in all textural properties. FTIR spectra exhibited bands representing the silica structure and DCCA-silica interaction.