Catalysts based on fiberglass supports: I. Physicochemical properties of silica fiberglass supports

The physicochemical properties and structure of supports prepared by leachi ng soda-silica fiberglass materials were studied using a set of physicochem ical techniques (BET; IR spectroscopy; transmission electron microscopy; an d Si-29, Na-23, Al-27, Cs-133, and Xe-129 (of adsorbed molecules) NMR spect roscopy). A matrix that corresponded in chemical composition to SiO2 was fo rmed at high degrees of leaching; however, it was considerably different fr om ordinary silica gels in properties. The structure and properties of this matrix are most adequately described by the model of a pseudolayer interca lation structure, which includes alternating layers of several silicon-oxyg en tetrahedrons separated by narrow (<4 w Angstrom) cavities. Considerable amounts of OH groups (similar to 5000 mu mol/g) are contained in these cavi ties, and these OH groups are different from the surface hydroxyl groups of ordinary globular silica. Although the interlayer spaces are small, compar atively bulky cations can be intercalated into them.