包气带不同深度土壤对甲苯和三氯乙烯的吸附研究

采用批实验研究了华北平原地下水中检出率较高的三氯乙烯和甲苯在沿污水河包气带不同深度土壤中的吸附情况。从3个地点分析结果来看,其中有机碳（OC）的质量分数均较低（最高为1.01%）。在河床和近河处土壤对甲苯和三氯乙烯的吸附总体上呈现出浅部土壤吸附性强的特点。在实验浓度范围内,土壤中无机矿物对有机污染物（特别是三氯乙烯）的表面吸附扮演了重要角色。土壤对甲苯的吸附表现出了强烈的非线性,而对三氯乙烯的吸附表现出了良好的线性关系。甲苯的吸附与土壤有机碳质量分数的关系要比三氯乙烯更密切,这说明了吸附作用过程与有机化合物的分子结构、疏水性等方面的性质也有关系。

Sorption of toluene and trichloroethylene to vadose zone soils at different depths

Toluene and trichloroethylene（TCE） were frequently detected in groundwater in the North China Plain.In this study,the sorption of toluene and TCE to soils of vadose zones was studied in batch experiments.The soil samples were taken from three different sites along the waste water rivers in the study area.The highest soil organic carbon content was 1.01%.The soils taken near ground surface showed a higher sorption capacity for toluene and TCE than that of the deep soils.In the experimental concentration range,sorption of organic contaminants,especially TCE,plays an important role in the overall sorption.Sorption of toluene to soils showed high nonlinearity,but linear sorption of trichlorobenzene to soils was observed.There was a closer relationship between sorption affinity and soil organic carbon content for toluene than that for TCE.This indicated that sorption process was also significantly influenced by the properties（e.g.,molecular structure,hydrophobicity）.