土壤不同有机质组分对菲的吸附特征研究

Sorption characteristics of phenanthrene by different soil organic matter fractions

采用批次实验,研究了三种不同类型土壤黄红壤、水稻土和草甸土的全土、重组、去松结态和紧结态4个组分对菲的吸附,结果表明,菲在不同土壤及其组分上的吸附等温线都能用Freundlich方程进行拟合,所有等温线都具有一定程度的非线性,指数N值的大小顺序基本都为全土>重组>去松结态>紧结态.除了黄红壤的紧结态比去松结态对菲的吸附容量KF值略小外,不同土壤及其组分对菲吸附的KF值以及有机碳归一化的KFoc值大小顺序都为紧结态>去松结态>重组>全土.不同类型土壤之间的KF值大小顺序为草甸土>水稻土>黄红壤,而KFoc值大小顺为水稻土>草甸土>黄红壤.KF值与有机碳含量之间呈显著性正相关(P<0.05),KFoc与N之间呈极显著负相关(P<0.001).土壤及其组分对菲的吸附强度与有机质的结构特征和聚合程度有关.

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 ofphenanthrene 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 ofTH 〉 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 KFo~ 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 ofphenanthrene in soils.