Floating photocatalysts based on TiO2 supported on high surface area exfoliated vermiculite for water decontamination

In this work, novel photocatalysts based on composites TiO2/high surface area vermiculite are described. These catalysts show the unique feature of floating on the water surface where optimum illumination and oxygenation occurs leading to a strong increase in their photocatalytic efficiency. The catalysts were prepared by impregnation of Ti(OCH(CH3)(2))(4) on exfoliated vermiculite (EV) followed by hydrolysis with HCl/H2O vapor and calcination. XRD, SEM, S-BET, TG/DTA analyses suggested the formation of anatase highly dispersed on the EV surface. Photocatalytic tests with the probe molecule the dye drimaren red showed that in non-stirred reactions the floating photocatalysts, especially TiO2(20 wt%)/EV, are very active whereas the TiO2 P25 sinks to the bottom of the reactor and remains inactive due to the poor illumination and oxygenation. (c) 2006 Elsevier B.V. All rights reserved.