Synthesis of nanoporous silica aerogel for adsorption and separation of hydrocarbons from water

Silica aerogels were synthesized successfully from sodium silicate precursor via ambient pressure drying and adsorption of BTX compounds were studied for the first time. The effect of various parameters such as type of alcohols, type of solvents, various percentages of modification agents and the type of modification agents in the synthesis of silica aerogels were investigated. The results show that by use of isopropylalcohol, n-hexane and 20% trimethylchlorosilane in modification step, nanoporous silica aerogels with very high specific surface area could be synthesized. Characterization of silica aerogel show that, 0.11 gr/cm3 density, 1430 contact angle, 600 m2/gr specific surface area, narrow pore size distribution (16 nm) and 3800 thermal stability. After synthesis and characterization, the adsorption properties of silica aerogels were investigated and compared. The high concentration, adsorption of various organic materials such as oil compounds, alkanes and BTX compounds were investigated. The results show that silica aerogels have much higher adsorption capacities than activated carbon, which for kerosene and crude oil is 19 and 78 times more adsorption capacity, respectively. At low concentration, the investigation of adsorption isotherm for BTX compounds show that silica aerogels conform with Freundlich isotherm with good accuracy.