Photodegradation of DDT with the photodeposited ferric ion on the TiO2 film.

The photodegradation capability of DDT has been enhanced by Fe/TiO2 film in a photoreactor with UV radiation. The optimal thickness of TiO2 for the DDT photodegradation was 2.94 microm with a 3-time coating, where the first-order rate constant was 0.077 min(-1). The optimal Fe3+(ferric ion) photodeposition amount was estimated as 3.7 x 10(-4) mg mm(-2) corresponding with 0.73 mg Fe3+ (mg TiO2)(-1). Photoremoval rate of DDT increased with an increasing pH value, while the pH value of solution decreased to acidic region during the DDT photodegradation. The photodegradation efficiency was 85% in 20 min with only TiO2 film and increased from 85% up to 96% by the photodeposition of 0.73 mg Fe3+ (mg TiO2)(-1) on TiO2 film as a sensitizer since the band gap energy of Fe2O3 (2.2 eV) is lower than that of TiO2 (3.0 eV).