Preparation And Characterization Of TiO₂-SiO₂Composite Aerogel

The aim of this dissertation is to synthesize supported TiO₂photocatalyst, using differentprocess to prepare agglomerate TiO₂-SiO₂aerogel and TiO₂-SiO₂aerogel spherule. Thecompound aerogel present not only the photocatalysis of TiO₂but also the high sorption of theporous materials, which can conquer the problem that the network of pure TiO₂aerogel isweak and the TiO₂powder is hard-recycle.Using cheap TiCl₄and industrial waterglass as raw materials, the TiO₂-SiO₂aerogelspherules were prepared by a spherule-dropping technology during sol-gel process. Themicrostructure, morphology and properties of the spherules were characterized by FTIR andSEM. The properties of adsorption and photocatalytic degradation of rhodamine B wereanalyzed. The results indicate that the gel spherules are better modified by ethanol/tetraethylorthosilicate（EtOH/TEOS） and with8mol/L NH3·H2O and0.2ml Span-80. The adsorption andphotocatalytic degradation ratio of rhodamine B promoted with the Si and Ti contentincreasing respectively, but it went against the better conglobate TiO₂-SiO₂aerogel spheruleswhen the Ti content were excessive.Using TiCl₄and industrial waterglass as raw materials, agglomerate TiO₂-SiO₂aerogels were synthesized via ambient pressure drying by sol-gel method, by usingtrimethylchlorosilane（TMCS） and EtOH/TEOS solution for the exchange/modification of thewet gel respectively. The microstructure, morphology and pore properties were studied bySEM, FTIR and BET measurement. The properties of adsorption and photocatalyticdegradation of rhodamine B were analyzed. The results indicate that the TiO₂-SiO₂aerogelsmodified by TMCS exhibit the better agglomerate. The density were0.14⁰.31g·cm^-3, surfacearea were684.9⁸02.7m²·g^-1, pore volume were1.72².28cm³·g^-1. TiO₂-SiO₂aerogels on thebasis of a Ti/Si molar ratio of3:1have the highest adsorption ratio for rhodamine B, and themolar ratio of1:2have the optimum photocatalytic degradation activity for rhodamine B.