The purpose of the study is the preparation of silica aerogels by using the hydro(solvo)thermal synthesis assisted sol-gel method, the preparation of SiO2 particle-added silica aerogels, and the investigation of their potential use in the environment and energy fields. It has been observed that the prepared silica aerogels can be used removal applications as an adsorbent for 4-nitrophenol, methylene blue, Victoria blue, bromophenol blue organic contaminants. The aerogel was modified nanoparticle as SiO2 and – NH2 group increasing adsorption capacity minimum 3 fold. The energy application, silica aerogel was used as a catalyst. It has been observed that silica aerogels progressed rapidly in the reaction of NaBH4 with methanol Again silica aerogel was modified increase catalytic activity and prolonging selflife. SiO2 particles embedded silica aerogel was used same reaction. Self methanolysis reaction was completed about 20 minute at 25 ºC. By using protonated silica aerogel, the reaction was completed about 4 minutes at same temperature.