Photocatalytic degradation of phenanthrene and pyrene on soil surfaces in the presence of nanometer rutile TiO2 under UV-irradiation

Photocatalytic degradation of phenanthrene and pyrene on soil surfaces in the presence of nanometer rutile TiO2 was investigated. After being spiked with phenanthrene and pyrene, soil samples loaded with different dosages of nanometer futile TiO2 (0, 1, 2, 3, and 4 wt%) were exposed to UV-irradiation for 25 h. The results indicated that the photocatalytic degradation of phenanthrene and pyrene followed the pseudo-first-order kinetics. The catalyst dosage of 2 wt% was chosen as the optimal one for further studies. According to the half-life, the degradation rate of the phenanthrene and pyrene on soil surfaces was related to their absorption spectra in soil and oxidation-half-wave-potential. In addition, the degradation of phenanthrene and pyrene increased along with increasing H2O2, light intensity and humic acids. All results indicated that the photocatalytic method in the presence of nanometer rutile TiO2 was an advisable choice for the treatments of PAHs polluted soil in the future. (C) 2010 Elsevier By. All rights reserved.