三氯乙烯在砂土和壤土中吸附的热力学研究

Adsorption of trichloroethylene and relevant influencing factors in loam and sandy soil

在实验条件下,采用批量平衡方法,研究了三氯乙烯在天然砂土和同一壤土不同深度中的吸附热力学特征,并对理论吸附量和不同粒径下的实际吸附量进行了对比.结果表明,试验范围内三氯乙烯不存在饱和吸附量,三氯乙烯在壤土和砂土中的吸附等温线都呈非线性,用Freundlich模型对TCE吸附数据的拟合效果较Langmuir模型好,不同粒径下实际吸附量和理论吸附量偏差不大;三氯乙烯的吸附等温线呈"L型";三氯乙烯在土壤中吸附量随温度的增加而减少,其吸附过程为自发的放热反应,吸附的推动力是氢键力;吸附容量和吸附强度差异性大.

Under the condition of temperature, a study on the thermodynamic adsorption of Trichloroethylene(TCE) in sandy and loam soil with different depths was carried out by batch adsorption methods. Meanwhile, theoretical adsorption and actual adsorption were compared on different particle sizes. The result showed that there was no saturated adsorption capacity in experimental range. The adsorption isotherms of TCE was non-linear both for the sandy and loam soils. The adsorption of TCE in soils fitted with Freundlich isotherm equation better than Langmuir model, and there was little deviation between theoretical and actual adsorption under different sizes; TCE adsorption isotherms resembled the L-type curves; TCE adsorption capacity was decreased with increasing temperature, and the sorption process was spontaneous exothermic reaction while the force of hydrogen bond was the driving force of sorption. In addition, there was significant difference(P<0.01) between organic matter and the size of soils.