Thermodynamics And Kinetic Research Of Typical PCBs Adsorption On Soils

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs). PCBs in environment are deposited in soils finally. Adsorption process of PCBs in soils has received considerable attention as one of the most important processes affecting the mobility, degradation and biological activity of PCBs in the environment. In this paper, adsorption behavior was studied systematically to figure out the model of adsorption and factors influencing the process.Based on the literature and the conditions of the laboratory, GC-ECD was used to determine PCBs concentrations. Studies on PCBs adsorption are crucial to elucidate the cycling and transformation of PCBs in soils. In this study, adsorption of PCB118 on soils from Jinan city and its relationship with organic matter content and particle composition were investigated by shock equilibrium method. The results showed that fast stage of adsorption in the soils was completed within 200 min, while the First-order equation gave the best fittings of the process. Variation of PCB118 adsorption was observed among soils with different properties. Soil organic matter contents significantly influenced the adsorption process. Soils with more organic matter adsorbed more and faster. Soil with smaller particles had better ability for adsorption, while the relation with adsorption rate was unmaked.The adsorption of polychlorinated biphenyls (PCBs) in soils and the factors that influenced the process were studied. Adsorption experiments of 2 PCBs (PCB118,95) were performed on soil samples taken from the Yellow River delta. The adsorption isotherm data could be described by the Langmuir equation. The adsorption process was influenced by several properties of the soils:a positive correlation was found between the PCBs adsorbing quantities (Cs) and the organic matter content of the soils; the clay content of soils had promotion effects on Cs during the process; no evident effects were found between Cs and pH; Cs on soil minerals was magnitude smaller than those on virgin soil, indicating that soil minerals had no direct influence on adsorption.