Phenanthrene adsorption on soils from the Yangtze River Delta region under different pH and temperature conditions

The phenanthrene (PHE) adsorption on soils from the Yangtze River Delta region under different pH and temperature conditions was studied in the laboratory. Results showed that the sorption of PHE on all soils was nonlinear and fitted to the Freundlich isotherm. The PHE adsorption on the soils is related to the content of organic carbons and the environmental conditions. There was a positive correlation (the correlation coefficient was 0.956) between the PHE adsorption and the soil organic carbon content. Adsorption on the soils at 15 °C ambient temperature was higher than at 25 °C, which was related to PHE solubility enthalpy. Adsorption on the soils in background solution at pH 5.0 was higher than in those at pH 6.2 and 7.5, which may be related to alteration of the hydrophobic character of humic substances. This study showed that intrinsic organic carbons influenced the adsorption of PHE, which was affected by environmental conditions, such as pH and temperature. Therefore, the characteristics of soil organic carbon should be considered first for implementing effective schemes for the remediation of contaminated soils and in the formulation of soil environmental quality standards.