Studies on photocatalytic degradation of harmful pollutants using metal decorated tio2 and srtio3 nano

Abstract

Mushroom growth of dye and textile industries in urban as well as rural riverside areas result in the accumulation of highly contaminated water bodies Similarly leaching of agro chemicals such as insecticides and pesticides intermediate equally contribute to water pollution These harmful pollutants are the real trouble makers for the water bodies present in our environment If these pollutants remain in the water bodies as such they will create severe ecological problems to the environment especially to human beings and other flora and fauna Hence prior treatment is needed before their disposal into the environment Several treatment methods such as membrane filtration, coagulation flocculation filtration adsorption ion exchange electrolysis etc to mitigate the problem but they have their own merits and demerits Most of these methods are not greener methods as they do not lead to complete destruction of the pollutants but only transfer the contaminant from one phase to another phase Hence a highly effective and environmentally benign process is sought all over the world Advanced oxidation process using heterogeneous, semiconductor based photo catalysts is the promising alternative technology for the purification of wide variety of pollutants Large number of semiconductors such as TiO2 Fe2O3 ZnO ZrO2 Nb2O5 WO3 SrTiO3 Bi2O3 SnO2 etc have been employed as photo catalysts for the destruction of the pollutants To date TiO2 Eg 3 2 eV has been proved to be one of the best catalysts for widespread environmental applications due to its high photosensitivity stability and nontoxicity SrTiO3 is another widely used semiconductor photo catalyst with similar band gap and similar properties However these two semiconductors present some drawbacks as i only small amount of photons are absorbed in the visible region with consequent need to irradiate with UV light ii high recombination rate for the photo produced electron hole pairs and iii deactivation in the absence of water vapour in gas solid systems