Synthesis and characterization of monolithic silica aerogel and silica aerogel with sol-gel method by using different starting materials

Silica aerogels are nano-structered materials, which have unusual features such as high porosity, high surface area, high thermal isolatioın value, very low density and very low dielectric constant. Due to these properties, they are used in many sectors such as construction, pharmacy, chemistry, electronic. Thus, the productiıon of silica aerogels forms the basis of many studies. In this study, silica aerogels was synthesized with left-gel method by using different starting substances and different parameters. In the first experimental study, silica sand and feldspar were used as a starting substance. In the preparation phase of sodium silicate solution was worked with different pH (2-7). In gelation phase, as a catalytic HCI and H2SO4 was used with different concentration (0,5-3M). As another parameter, drying process was realized with different oven temperature (50-130 ?C ). Sodium silicate solution, of which pH value was 6, was obtained both silica sand and feldspar. In gelation phase, after HCl katalizör was used gel was dried in 110 ?C. Silica aerogels were obtained. The surface area value of these silica aerogels was determined as 744 m2/g, 802 m2/g in order and average pore diameter was 31 A. In another study, monolithic silica aerogel was synthesized with left-gelş method, using tetraetilortosilikat (TEOS) as silica source, polietilen glycol (PEG) and HNO3 catalytic for monolithic silica aerogel, which was synthesized in different catalyst concentrations and in environment either with urea or not, was done charactereization study. As a result of these studies, ıt was observed that not using area and with 0,6 m HNO3 the best surface area result that was obtained was (1200 m2/g).