Wen Bei, Zhang Jing-Jing, Zhang Shu-Zhen, Shan Xiao-Quan, Khan Shahamat U, Xing Baoshan
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China.
Environ Sci Technol. 2007 May 1;41(9):3165-71. doi: 10.1021/es062262s.
This study was undertaken to provide an insight into the effect of heterogeneous soil organic matter (SOM) on the sorption of phenanthrene. Humic acid (HA) and humin were extracted from a peat soil. Humin was further fractionated into bound-humic acid (BHA), lipid, and insoluble residue (IR) fractions. Heterogeneous natures of these fractions were characterized by elemental analysis, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and solid-state 13C NMR. Aliphaticity of the fractions followed the order lipid >BHA > HA > IR, while the polarity order was IR > BHA> HA > lipid. Sorption of phenanthrene on these fractions fitted the Freundlich equation, suggesting that phenanthrene sorption isotherms of lipid were almost linear (N = 0.993), while those of HA, BHA, and IR were nonlinear, with N values ranging from 0.723 to 0.910. The N values followed the order lipid > HA > BHA > IR and were significantly correlated inversely with their polarities (p < 0.05). Organic carbon-normalized sorption coefficients (K(FOC)) were independent of aliphatic or aromatic contents of the SOM fractions. The results suggested that SOM, especially for the humin fractions, was highly heterogeneous in terms of elemental composition, structure, and polarity. Such heterogeneity was considered to be responsible forthe nonlinear sorption of phenanthrene.
本研究旨在深入了解异质土壤有机质（SOM）对菲吸附的影响。从泥炭土中提取了腐殖酸（HA）和胡敏素。胡敏素进一步分离为结合腐殖酸（BHA）、脂质和不溶性残渣（IR）组分。通过元素分析、紫外可见光谱、傅里叶变换红外光谱和固态13C核磁共振对这些组分的异质性进行了表征。各组分的脂肪族性遵循脂质>BHA>HA>IR的顺序，而极性顺序为IR>BHA>HA>脂质。菲在这些组分上的吸附符合弗伦德利希方程，表明脂质对菲的吸附等温线几乎呈线性（N = 0.993），而HA、BHA和IR的吸附等温线为非线性，N值范围为0.723至0.910。N值遵循脂质>HA>BHA>IR的顺序，且与它们的极性呈显著负相关（p < 0.05）。有机碳归一化吸附系数（K(FOC)）与SOM组分的脂肪族或芳香族含量无关。结果表明，SOM，尤其是胡敏素组分，在元素组成、结构和极性方面具有高度的异质性。这种异质性被认为是菲非线性吸附的原因。
