Preparation of Monolithic TiO_2 Aerogel via Ambient Drying and Photocatalytic Degradation of Oily Wastewater

The monolithic TiO2 aerogel was sucessfully synthesized at ambient pressure through Sol-Gel technique with TBT as the raw material and its photocatalyst property for degradation of the aqueous emulsion of crude oil in the Bohai Sea was investigated.During the ambient drying process,aging liquor and pinhole drying technology were found to be critical to the properties of TiO2 aerogels.It was shown that the pinhole drying was favorable in reducing the asymmetric stress on the framework of TiO2gel in the drying process and the TEOS-Ethanol or TBT-Ethanol solution as the aging liquor for TiO2wet-gel could enhance the strength of TiO2 gel skeleton.Combining these effects,the cracking problem of TiO2 alcohol gel in the drying could be solved and the high-performance TiO2 aerogel monolith was eventually achieved.The most integrated TiO2aerogel block exhibited low density(0.184 g/cm3) and high specific surface area(389.5 m2/g).By calcinations at high temperature,the TiO2 aerogels changed from amorphous to anatase structure.The photocatalytic properties of the heat-treated TiO2 aerogels were investigated via the degradation experiment for the aqueous emulsion of crude oil in the Bohai Sea.The results of photocatalytic experiments showed that the catalytic degradation rate was up to 91% with the addition of TiO2aerogel of 400 mg/L.