Photocatalytic Degradation Of Polycyclic Aromatic Hydrocarbons Catalyzed By TIOZ In Aquatic System

Photocatalytic Degradation of Poly cyclic aromatic HydrocarbonsCatalyzed by TiO2 in Aquatic systemWen Sheng (Organic Geochemistry) Directed by Sheng Guo-ying, Fu Jia-mo and Zhao Jin-caiPolycyclic aromatic hydrocarbons (PAHs) are among the 129 priority pollutants listed by US EPA. They mostly derive from the incomplete combustion of the fuel. Many of them are toxic and carcinogenic for mammal and human being. With the development of the world industry, the use of fossil fuel, release of the wastewater and the accidents of the oil leakage, the pollution of the PAHs in water is more and more serious. The photocatalytic degradation is an efficient way to delete such almost non-degradable pollutants. In this article, phenanthrene and pyrene are used as examples to study the photodegradation of PAHs catalyzed by TiC>2 in aquatic system. UV-vis spectrophotometer. IR spectrometer, chemical oxygen demand (COD) measurements and GC-MS analytical techniques were used to describe the degradation kinetics, monitor the formed intermediates and to reveal the photodegradation pathway. We've made some progress as follows:(1) PAHs is first dissolved in organic resolvent and then TiO2 is added in. After the solution is volatilized. PAHs is absorbed on the surface of TiO2. Use this method, it is relatively easy to study the photodegradation of PAHs catalyzed by TiO2 in aquatic system. Under this study system, the infusibility of PAHs is not a problem. It can also be used in the study of the photocatalytic degradation of some other water non-resolvable organic compounds, so we can study the degradation kinetics and pathway of such kind of organic matters with this more easy method. The establishment of this method is a breakthrough in the field of study of photodcatlytic degradation of such water non-resolvable organic compounds.(2) Some factors affecting the photodegradation rate are studied, including amount of TiOz, pH, surface coverage, concentration of Fe3+. It is found that the first two factors almost have no effect on it. But with the increasing of surface coverage and concentration of Fe3+, the degradation rates decrease.(3) Through the study on the variation of UV-vis spectrophotometer, IR spectrometer and CODcr value, we find the production of some intermediate products. And following the progress of the reaction, the reactors and the intermediate products are all gradually mineralized, and all disappear at last.(4) GC-MS is used to detected the intermediate products during the reaction, some intermediate products are confirmed and the photodegradation pathway of the PAHs are described. The investigation also ulteriorly proved the mechanism of reaction of TiOj on the organic compounds.