有机碳与温度对土壤吸附乙基叔丁基醚的影响

Effects of Organic Carbon Content and Temperature on Sorption of ETBE to Chinese Reference Soils

作为具有很大市场潜力的汽油添加剂乙基叔丁基醚(ETBE),国内对其在地下水土中的污染风险评价与迁移归宿研究甚少。通过静态吸附实验研究了ETBE在我国六种不同有机碳含量的标准土壤样品中的吸附特性。研究表明,在1~143 mg/L的实验浓度范围内ETBE在土壤样品中的吸附行为均呈良好的线性关系。ETBE在各土壤样品中吸附分配系数的差异与土壤有机碳组成及无机矿物吸附在总吸附中的贡献比例有关。温度对吸附有着明显影响,土样对ETBE的平衡吸附量随温度的升高而降低,焓变(ΔH)<0表明吸附为放热过程。ΔH范围为-8^-32 kJ/mol,表明ETBE在土样中的吸附同时受范德华力和其他特殊作用的影响。

Ethyltert-butyl ether （ETBE） is a promising gasoline additive and its utilization might cause groundwater contamination problem. However, few researches have been done on ETBE contamination or transport in soil and groundwater system. The sorption characteristics of ETBE to six Chinese reference soils of different organic carbon contents were studied by batch experiments under different temperatures. Results showed that the sorption of ETBE to six different soils can be well described by linear sorption isotherms in the experimental concentration range of 1-143 mg/L. Difference in ETBE sorption coefficients from different soils might be caused by difference in soil organic carbon components and contribution of soil mineral sorption to total sorption. Negative sorption enthalpy indicated that the sorption process was exothermic, in a range from-8 to -32 kJ/mol, which indicated that van der Waals forces and other specific interactions happened simultaneously in the sorption process.