Effect of soil condition on UV photodegradation of PAHs and kinetics study

The effects of soil depth and particle sizes on photodegradation of polycyclic aromatic hydrocarbons(PAHs) under UV irradiation were studied.The results show that the photodegradation rate of benzo[a]pyrene and pyrene decreased as the soil depth increased.The order of photodegradation rate is as follow : 1.0mm1.6mm 2.0mm2.4mm4.0mm.After modeling the experimental data,the photodegradation of benzo[a]pyrene and pyrene accord to first order dynamical model.Soil particle sizes obviously influenced photodegradation of benzo[a]pyrene,pyrene and phenanthrene.In three different particle sizes the photodegradation rate of 1mm soil was the fastest,and the photodegradation rate of different PAHs complied the following order: benzo[a]pyrene pyrenephenanthrene.