KINETICS DYNAMICS OF PHOTOCATALYTIC DEGRADATION OF PAHs ON SOIL SURFACE UNDER SOLAR IRRADIATION

This paper studied the soil borne PAHs(polycyclic aromatic hydrocarbons)photodegradation and photocatalytic degradation under solar irradiation with phenanthrene,pyrene and benzo[a]pyrene as target contaminants.The effect of soil pH and humic acids(HA)on the kinetics of photodegradation was studied.The effect of soil pH on the photocatalytic degradation of PAHs was investigated with nano TiO2 or Fe2O3 semi-conducter as catalysts.The results showed that the photodegradation rate of PAHs in acidic or alkaline conditions was greater than that in neutral condition under solar light irradiation.The photodegradation rate of diferent PAHs follows the order of:BaPPyrPhe at the same soil pH.HA accelerated PAHs photodegradation.HA played a sensitizing role during the PAHs photodegradation.HA concentration of 5 mg·kg-1 could efficiently sensitized the PAHs photodegradation.In acidic conditions,the photocatalytic degradation rate of PAHs using nano TiO2 or Fe2O3 semi conducter as catalysts were the greatest,while in neutral and alkaline conditions the difference was not obvious.