MECHANISTIC STUDIES OF WATER DETOXIFICATION IN ILLUMINATED TIO2 SUSPENSIONS

The destruction of toxic halogenated hydrocarbons in waste water effluents or ground water wells is a problem of growing importance in our industrial society. Since conventional method such as chemical oxidation or microbial treatment are often not efficient for the destruction of these toxins, alternative routes for detoxification are required. It has been shown that semiconductor particles can be used as photocatalysts which are capable of inducing the complete mineralization of many of these hazardous compounds. Detailed mechanistic studies are presented here which have been carried out to investigate the potential use of concentrated solar illumination as the source of irradiance in those photocatalytic systems. Thus the influence of light intensity, temperature and pH on the overall yield of the destruction of halogenated hydrocarbons in aqueous suspensions containing titanium dioxide powder has been studied in detail. Models are presented to explain the observations made with chloroform as the probe molecule and to enable predictions of the efficiency of this method for "real world" applications.