Preparation of TiO₂ thin films on polypropylene beads by a rotating PCVD process and its application to organic pollutant removal

The TiO₂ thin films were coated on the polypropylene (PP) beads by a rotating cylindrical plasma chemical vapor deposition (PCVD) process and the photocatalytic activity of TiO₂ thin films was examined for the photodegradation of phenol in aqueous solution. The TiO₂ thin films grow more quickly on the PP beads with increasing the rotation speed of the reactor and with decreasing the number of PP beads. The photodegradation rate of phenol by TiO₂ thin films on the PP beads increases as the initial phenol concentration increases or as the number of PP beads coated with TiO₂ thin films increases in aqueous solution. The rotating cylindrical PCVD process can be a good method to coat the high-quality TiO₂ thin films on the particles. It is proposed that the particles coated with TiO₂ thin films can be applied to the removal of water pollutants with high efficiency.