Floating photocatalysts based on TiO2 grafted on expanded polystyrene beads for the solar degradation of dyes

In this work, a highly active, low cost, simple and robust floating photocatalyst based on TiO2 P25 grafted on expanded polystyrene (EPS) beads was developed. SEM and TG analyses showed that ca. 18 wt% of TiO2 can be permanently grafted on the surface of EPS particles. This floating photocatalyst showed high efficiency for the degradation of three different dyes, i.e. methylene blue, indigo carmine and drimaren red, with UV (Hg 245 nm) or solar irradiation under constrained conditions, i.e. non-stirring and no-oxygenation. Under the same conditions pure TiO2 showed very low activities. The floating photocatalyst can be reused for at least four consecutive times without any significant decrease on the discoloration and TOC removal after each reuse.