Adsorption of Phenanthrene in Black Soil and Effect of Freeze-thawing Cycles on Its Extraction

When the Hydrophobic organic compounds leak into the soil, with the contact time increase between the hydrophobic organic compounds and the soil, it can lead to the extraction rate and the bioavailability decrease. We used phenanthrene as target pollutant to study the adsorption behavior of phenanthrene in original black soil and three different fractions soil. The effect of different freeze-thawing cycles on its extraction was also studied by using standard addition method. The results shown that the adsorption isotherm fit Freundlich equation well (R²≥0.9530) and 1/n was in the range of 0.7695~1.0836. The extraction of phenanthrene in black soil and its different fractions can be significantly reduced by freeze-thaw treatment, and the extraction rate decreased the most after the first time of freeze-thawing cycles. So, the aging effect should be considered to evaluate the environmental risks of organic pollutants in soil.