应用平衡法研究了湿地土壤不同有机组分对硝基苯和苯胺的吸附行为.结果表明,吸附等温线经拟合后均符合Freundlich模型,可决系数分别为R^2=0.983~0.997,R^2=0.963~0.991(p〈0.01,n=5),土壤不同有机组分对硝基苯和苯胺的吸附表现为非线性特征,其吸附过程与有机质含量和结构有关.硝基苯和苯胺在湿地土壤中的吸附主要受腐殖酸、易氧化有机质组分和脂类化合物的影响,其中腐殖酸对硝基苯和苯胺具有最大的吸附容量;脂类化合物表现为与硝基苯、苯胺竞争土壤有机质结构中的吸附位点,去除脂类化合物后残余物的吸附量增大;矿物组分对硝基苯和苯胺的吸附是次要的,吸附容量仅为2.31mg·kg^-1和3.63mg·kg^-1.硝基苯和苯胺的Koc值分别按如下顺序增加:碱提取残余物〈原始土〈过氧化氢氧化残余物〈苯/甲醇提取残余物,原始土〈苯/甲醇提取残余物〈过氧化氢氧化残余物〈碱提取残余物.
Batch equilibrium experiments were performed to assess adsorption characteristics of nitrobenzene and aniline by humus fractions of selected wetland soils. The results showed that adsorption isotherms fit the Fruendlich model R^2 = 0. 983 - 0. 997, R^2 = 0. 963 - 0. 991 (p 〈 0.01, n = 5 ), and all of the isotherms were nonlinear. The differences in the adsorption coefficients(Kl) were mainly due to the content and structure of soil organic matter. Humic acids, oxidizable fraction and lipids were the main fractions affecting the sorption capacity. The humic acids had the maximum adsorption capacity for nitrobenzene and aniline, the lipids naturally present in the soil strongly compete for hydrophobic sorption sites within the soil organic matter, and the adsorption capacity of the mineral surface for nitrobenzene and aniline was only 2.31 mg· kg^-1 and 3.63 mg· kg^-1,respectively. Koc of nitrobenzene increased in the following order: soil extracted by alkali 〈 natural soil 〈 soil oxidized by H2O2 〈 soil extracted by benzene/methanol while the Koc for aniline increased in the order natural soil 〈 soil extracted by benzene/methanol 〈 soil oxidized by H2O2 〈 soil extracted by alkali.