Retention of Nonionic Organic Compounds on Thermally Treated Soils

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• 作者：Haijun Zhang ; Sufang Zhao ; Ying Yu ; Yuwen Ni ; Xianbo Lu ; Yuzeng Tian ; Jiping Chen
• 刊名：Environmental Science & Technology
• 出版年：2010
• 出版时间：May 15, 2010
• 年：2010
• 卷：44
• 期：10
• 页码：3677-3682
• 全文大小：157K
• 年卷期：v.44,no.10(May 15, 2010)
• ISSN：1520-5851

文摘

To achieve a higher efficiency of thermal remediation of soil contaminated with organic compounds, the retention mechanisms of organic compounds on thermally treated soil need to be understood adequately. In this study, a soil-column gas chromatography approach was developed to determine the soil-air partition coefficients (K_SA) at 300 °C for a diverse set of nonionic organic compounds bearing many different functional groups; and the retention mechanisms of these organic compounds on two typical soils, isohumisols and ferralisols, were characterized using a polyparameter linear free energy relationship (pp-LFER). The K_SA values (mL g⁻¹) of typical volatile organic compounds (VOCs) with lower boiling points were <1.5 and in some cases even below 1.0, suggesting the rapid removal of VOCs from soils at 300 °C. Moreover, the K_SA values were found to be a strong function of the soil-column temperature T (K), and be almost independent of the carrier-gas flow rate. Significant differences in molecular interactions were noted among various soil-solute pairs. The relative contributions of nonspecific van der Waals forces to the retention of test polar solutes were higher on isohumisols than on ferralisols. In contrast to the reported pp-LFER models for natural soils and soil components at normal environmental temperatures, our results suggest that elevated temperature remarkably reduces H-bond interactions between polar organic compounds and the soil matrix, thus allowing accelerated desorption of polar organic compounds from soils during thermal treatment.