III International Conference

PP-III-95PROPERTIES AND ACTIVITY OF Ti-Si AEROGELS IN PHOTODEGRADATIONOF ORGANIC COMPOUNDSBrodzik K., Walendziewski J., Stolarski M.Wroclaw University of Technology, Faculty of Chemistry, Department of Fuels Chemistryand Technology, ul. Gdańska 7/9, 50-344 Wrocław, PolandE-mail: jerzy.walendziewski@pwr.wroc.plHigh temperature supercritical dried (HTSCD) titania-silica aerogels fromtetraethoxysilane (TEOS) and titanium butoxide (TB) were prepared by using two methods:precursors co-hydrolysis and silica gel impregnation method. Titania content in aerogels wasvaried in the range 10 - 30 wt %. The photocatalytic activity studies were carried out in aphotoreactor containing 20 and 50 ppm water solutions of model organic compound –methylene blue (MB). Prepared aerogels were meso-, macroporous materials with surfaceareas up to 1150 m 2 /g and pore volumes up to 6.7 cm 3 /g. Up to 96 and 76 % (respectively for20 and 50 ppm systems) decolorization of solutions was stated after irradiation, as measuredby UV spectroscopy.It was found that highly porous titania-silica aerogels can be prepared by two describedmethods, namely co-hydrolysis and silica gel impregnation, with use of TB as a titaniaprecursor. Good performance of prepared aerogels in photodegradation of methylene bluefrom aqueous solutions is a result of accessibility of well developed, photocatalytically activetitania species. Influence of alcohol used during the synthesis of sol-gel photocatalysts is moreevident in case of co-hydrolysis method than in case of impregnation. Application of simple,co-hydrolysis method leads to materials containing isolated titania on titania-silica matrix.Titania is better utilized in case of aerogels with its relatively small content, what confirmsour previous studies concerning salicylic acid photodegradation.647