Demineralization of organic pollutants on the dye modified TiO2 semiconductor particulate system using visible light

Photodegradation of organic pollutants, viz. phenol, chlorophenol, 1,2-dichloroethane and trichloroethylene in water has been achieved on the surface of TiO2 semiconductor modified with thionine and eosin Y by using visible light. After 5 h of irradiation with a 50 W tungsten lamp, over 55–72% degradation of pollutants is achieved. A working mechanism involving excitation of surface bound dye, followed by charge injection into the TiO2 conduction band is proposed.