Preparation and characterization of silica-titania aerogel-like balls by ambient pressure drying

A method to prepare silica-titania aerogel-like balls (STABs) with photocatalytic activity was reported. Silica-titania sol was prepared by mixing self-made titania sol with commercial silica sol. Silica-titania gel balls were prepared by ball-dropping method (BDM) and sol-gel process. The mechanical strength of gel balls is obviously improved by immersing them in TEOS/alcohol solution before the start of gel drying procedure. These strengthened wet gel balls were dried at ambient pressure and STABs with small shrinkage were obtained. Characters of porous structures of STABs were characterized by transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) method. STABs also display excellent photocatalytic activity for the degradation of methylene blue as a simulated aqueous organic pollutant in waste water.