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Sorption characteristics of phenanthrene by different soil organic matter fractions |
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Abstract Three fractions of organic matter (heavy fraction (HF), heavy fraction without the loosely combined humus (WLH), and tightly combined humus (TH) were separated from three soil types named yellow-red soil, paddy soil and meadow soil. Batch experiments were conducted to study the sorption of phenanthrene by HF, WLH, TH and bulk soils (BS). Results showed that all sorption isotherms of phenanthrene by the different organic matter fractions and bulk soils fitted Freundlich equation and were nonlinear in some degree. The values of Freundlich exponent coefficient (N) followed the order of BS > HF > WLH > TH. The sorption capacity (KF) and its organic carbon normalized parameter (KFoc) for phenanthrene were in the order of TH > WLH > HF > BS, except that KF of TH was less than that of WLH in yellow-red soil. The KF values of different soils were in the order of meadow soil>paddy soil>yellow-red soil. However, the KFoc values were in the order of paddy soil>meadow soil>yellow-red soil. The KF values had a significantly positive correlation (P<0.05) with the organic carbon content of sorbents, and the KFoc values had a very significantly negative correlation (P<0.001) with the N values. The structural characteristics and degree of polymerization of organic matter were related to the sorption of phenanthrene in soils.
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Received: 27 September 2012
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