چكيده به لاتين
Abstract
Polycyclic aromatic hydrocarbons and heavy metals are two groups of pollutants that coexist with different concentrations in different soils. However, simultaneous existance of hydrocarbons and heavy metals is growing up in the soil around urban complexes, gas stations, mines and main roads. So it is very important to determine the behavior of these pollutants in the soil and the factors affecting their behaviors. Absorption and desorption are important processes that affect the behavior of pollutants in the soil. In this study, we have tried to determine the effect of soil organic matter and heavy metals on adsorption and desorption of phenanthrene as representative of polycyclic aromatic hydrocarbons in soil. For this purpose soil samples with three percent of organic matters, 12.345, 18 and 23%, were prepared.The adsorption isotherms of heavy metals consist of lead, nickel and zinc in each of the soil samples were obtained. Then the soil samples were spiked with lead, nickel, zinc and phenantherene. The results of batch expriments with ratio of 2 to 1000 showed that increasing soil organic matter greatly increase the adsorption of phenantherene. The presence of heavy metals in the soil increase the absorption of phenantherene, too.
Desorption experiments with three solutions consist of CaCl2 0.01M as a basic solution, EDTA 0.01M + TWEEN80 7.5% (v / V) and EDTA 0.01M + Triton X100 7.5% (v / V) was performed. The results showed that 59 to 65 percent of lead, 69 to 75 percent of nickel and 75 to 85 percent of zinc were desorbed. Desorption of phenantherene decresed by increasing soil organic matter and peresence of heavy metals.
Keywords: Polycyclic aromatic hydrocarbons, Heavy metal, Adsorption isotherm, Desorption
