Photocatalytic destruction of organic pollutants in a Pt/TiO 2 semiconductor particulate system

A number of organic pol lu tants that are emitted from various industrial sectors, agricultural and even domestic. fields cause contamination of water (even when they are present in low concentrations) as well as ai r and pose severe ecologica l problem as the biodegradation of the above pollutants is often very slow. The photocatalytic route using semiconducting TiO~ particle towards detoxification of water contaminated with organic pollutants is of current -i nterest ' · R • However, the main drawback of TiOz semiconductor is that it absorb~ a small portion of solar spect rum in the UV region (band gap energy of Ti02 is J .2eV) . Hence. in order to harvest maximum solar energy, it is essentia l to shift the absorption threshold towards yisible region. Dye sensitization. '5 is an alternative method in which dye (sensitizer) adsorbed on Ti02 surface gets excited by absorbing visible light and effec ts charge transition at subbandgap excitation to permit photocatalytic processes. In presence of visible light, ferric ions are believed to behave as sensitizers in photoassisted e lec tron transfer process I . 17 . Therefore, in order to examine the Ti02 catalysed photodegradation of orga nic pollutants using visible light we have undertaken the present investigation. We wish to report herein the preliminary results on photodegradat ion of some common orgal1lc pollutants. viz., phenol , chl orophenol and tri chl oroethylene ca talysed by suspended PtlTi02 system in presence of FeCI) by us ing a SOW tungsten lamp.