چكيده به لاتين
Abstract
Several factors affect the sorption and desorption of PAHs in soil. Heavy metals and organic matters of soil are known to be the most affection parameters on sorption and desorption of PAHs. In this research the main objective is the effect of organic matter and heavy metals on sorption and desorption of PAHs.
In this thesis research, sorption of organic matters to the kaolinite clay soil was tested by batch experiments. After that, , two soils with different amount of organic matter were prepared by using the result of the batch experiments, in order to determine sorption of Nickel, Zinc and Lead on the basic kaolinite soil and the soils with different organic matter. Based on the results from these experiments, three soils containing heavy metals and different amount of organic matters and three soils with only different amount of organic matters were made. Finally these six type of soils were used to determine sorption and desorption of PAHs.
The results indicate that 5.47% and 11.18% increase organic matter will increase the sorption of Nickel, Lead and Zinc, The reasons are new places for the sorption and increasing the cation exchange capacity of soil. Moreover the presence of heavy metals and organic matters will boost the sorption of Phenanthrene. There are some hydrophobic areas on the surface of the organic matters in soil structures, which can increase the sorption of Phenanthrene. Heavy metals will change the clay surface into a hydrophobic surface and also interaction of the clayey minerals and followed by organic matters, can increase Phenanthrene sorption in soil.
On the other hand, increasing the amount of organic matter in soil will decrease desorption of PAHs from soil media which is due to the harder fracture in bonding between heavy metals and organic matters. Also it is stated that heavy metals and organic matters will decrease desorption of phenanthrene.
Keywords: Polycyclic aromatic hydrocarbons (PAHs), Heavy metals, Organic matters, Sorption, Desorption, Kaolin.
