中文摘要：

采用批平衡试验方法,模拟了土壤的3种主要吸附活性组分〔K＋饱和蒙脱石（K＋-Mont）、胡敏酸-蒙脱石复合体（HA-Mont）和生物质炭（BC）〕对2种构型的一氯代联苯（PCBs）〔非共平面阻转类2-氯联苯（2-CB）和共平面类4-氯联苯（4-CB）〕的吸附特性。结果表明：线性方程均能很好地拟合3种模拟土壤固相组分对多氯联苯的吸附,2种PCBs的吸附分配系数（Kw）从大到小依次均为BC、HA-Mont和K＋-Mont。通过不同温度下吸附等温线的热力学分析,发现K＋-Mont对PCBs的吸附驱动力主要为表面吸附作用和疏水作用,蒙脱石矿物的层间是重要吸附域;HA-Mont对PCBs的吸附驱动力主要为分配作用;而BC对PCBs的吸附域主要为芳香性微孔表面,表面和PCB分子间的π-π作用是吸附的主要驱动力。尽管2种PCBs的疏水性相近,共平面类4-CB在3种吸附剂上的吸附量均显著大于阻转类2-CB,原因主要为非共平面的2-CB的空间位阻效应阻碍了2-CB进入纳米尺寸的蒙脱石矿物层间或BC的微孔吸附域,有机污染物分子的空间结构对污染物在土壤中的吸附迁移过程起重要作用。

英文摘要：

Characteristics of the adsorption of orthosubstituted nonplanar 2-chlorobiphenyl （2-CB） and nonorthosubstituted coplanar 4-chlorobiphenyl （4-CB） on three major simulated sorptive soil components： K＋ saturated montmorillonite（K＋ Mont）, humic acidclay mineral complexes（HAMont） and biochar（BC） were studied through batch equilibration experiments. Results show that the linear eqatio could be used to fit the adsorption isotherms of PCBs on all the threeabsorbents with the adsorption coefficient Kw being in the order of BC〉HAMont〉K＋ Mont. Thermodynamic analysis of theadsorption isotherms as a function of temperature indicated that both surface adsorption and hydrophobic effect were thedriving forces of the PCBs sorption on K＋ Mont, while partition was the major one of the PCBs sorption on HAMont, forthe interlayer spaces of montmorillonite are the major adsorption area, and the aromatic nanoporous surface of BC and theππ effect between PCB molecules were the major driving forces, for the surface was the major adsorption area of BC. Thesorption of 4-CB was higher than that of 2-CB on all the three absorbents despite that 2-CB and 4-CB are similar in hydrophobicity, which suggests that steric effect of the nonplanar structure prevents 2-CB from accessing nano sized interlayer spaces of montmorillonite or nanopores on the surface of BC. All the findings in this study indicate that the three dimensional structures of organic pollutant molecules play an important role in their sorption and translocation in the soil.