PHOTOCATALYTIC DEGRADATION OF PYRENE IN POROUS Pt/TiO2-SiO2 PHOTOCATALYST SUSPENSION UNDER UV IRRADIATION

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt/TiO2-SiO2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was prepared by a simple heat treatment of the compacted powder mixtures of anatase TiO2 and amorphous SiO2 with camphor as a pore directing template, followed by coating platinum by the dip-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive analysis of the X-ray (EDX) system, and Brunauer-Emmett-Teller (BET) were used to characterize PPtPC. The degradation kinetics of pyrene in different experimental conditions, such as initial concentration of pyrene, oxygen concentrations, pH, and temperature, were investigated. The durability of PPtPC was also tested. The results indicate that the structure of TiO2 in PPtPC is anatase. The aggregated size of PPtPC is in the range of 10-100 mu m, the mean pore diameter is 3 nm, and the BET surface area is 109 m(2)g(-1). The photocatalytic degradation process of pyrene follows pseudo-first-order kinetics. The rate constants increase as the initial concentration of pyrene and pH decrease. Higher temperature slightly enhances the rate constant. The dissolved oxygen in the photocatalytic degradation process is not as important as in the photolysis process. The recovered PPtPC still shows high photoactivity. This work suggests that PPtPC offers a promising method for high molecular weight PAH removal.