Hierarchical Porous SiO 2 Cryogel via Sol-Gel Process.

The aim of this research work was to develop a new, low-cost and low-energy-consuming preparation route for highly porous silica systems. The precursor gel systems were synthesized by sol-gel chemistry. The starting materials were TEOS and water glass in the sol-gel syntheses. The effect of the chemical composition, the catalysis, the pH, and the additives were investigated on the structure and porosity of the cryogels. The gel systems were treated by freeze-drying process to obtain porous cryogel silica products. The cryogel systems possess hierarchical structures. The conditions of the freeze-drying process were also studied to increase the porosity. Small angle X-ray measurements, scanning electron microscope technique, and infrared spectroscopy were applied for the investigation of gel and cryogel systems.