Adsorption of anthracene on organo-mineral aggregates of soils

Organo-mineral aggregates in various fractions were isolated from soil samples by ultrasonic dispersion in water followed by sedimentation. The soils included: red soil collected from Jiangxi, fluvoaquic soil collected from Beijing and black soil collected from Heilongjiang. The physicochemical properties of the different particle-size fractions were determined. The adsorption behaviour of polycyclic aromatic hydrocarbon on organo-mineral aggregates of the three kinds of soils were investigated using anthracene as the model substrate. The adsorption isotherms in all fractions were well described by the advanced Freundlich equation and demonstrated increases in the adsorption capacity and nonlinearity with particle size decreasing. The correlation between K_F values of anthracene and organic matter contents of organo-mineral aggregates was good, while the cation exchangeable content of black soil aggregate was dependent on K_F values.