Photodegradation of Polycyclic Aromatic Hydrocarbon Phenanthrene on Soil Surface

Photodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) is a main environmental behavior and plays an important role in the fate of PAHs in environment. In order to understand the photodegradation law of Polycyclic Aromatic Hydrocarbons(PAHs)in soil, aeolian sand in blow-sand region of Northern Shaanxi was chosen as typical soil and phenanthrene (Phe) as typical pollutant of PAHs. Photodegradation law of Phe on soil surface was simulated. In addition, effects of initial Phe concentration, light intensity, time and pH on photodegradation of Phe in aeolian sand was assessed. Results show that the photodegradation of Phe followed pseudo first-order kinetics. Photodegradation rate constant of Phe increased with the increasing of irradiation intensity which the order was as followed: 125W>100W>75W>50W. Irradiation intensity enhances photodegradation of PAHs on soil surfaces. Photodegradation half-life of Phe ranged from 2.474 hours to 3.095 hours under different irradiation intensity. Degradation rate increases as pH increase and photodegradation is more rapid in alkaline medium. Photodegradation rate is the lowest as initial concentration is the largest.