Sorption and Desorption of Naphthalene by Soil Organic Matter

来自 EBSCO

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阅读量：

176

作者：

AS Gunasekara，B Xing

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摘要：

Nonlinear isotherm behavior has been reported for the sorption of hydrophobic organic compounds (HOCs) in soil organic matter (SOM), but the exact mechanisms are unknown. Our objective was to provide insight into the sorption mechanism of HOCs in SOM by studying the sorption-desorption processes of naphthalene in a mineral soil, its humic fractions, and lignin. Additionally, humin and lignin were used for studying the effects of temperature and cosolvent on HOC sorption. All isotherms were nonlinear. The humin and lignin isotherms became more linear at elevated temperatures and with the addition of methanol indicating a condensed to expanded structural phase transition. Isotherm nonlinearity and hysteresis increased in the following order: soil humic acid (HA) < soil < soil humin. Of the samples, aliphatic-rich humin exhibited the largest degree of nonlinearity and had the highest sorption capacity for naphthalene. High nonlinearity and hysteresis in humin were most likely caused by its condensed structure. A novel aliphatic, amorphous condensed conformation is proposed. This conformation can account for both high sorption capacities and increased nonlinearity observed for aliphatic-rich samples and can explain many sorption disparities discussed in the literature. This study clearly illustrates the importance of both aliphatic and aromatic moieties for HOC sorption in SOM.

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关键词：

FA, fulvic acid HA, humic acid HOC, hydrophobic organic compound KF, sorption capacity K'FOC, organic carbon&#150 normalized sorption capacity SOM, soil organic matter

DOI：

10.2134/jeq2003.0240

被引量：

440

年份：

2003