不同解吸剂对污染土娄土铜铅的解吸动力学研究

Kinetics of copper and lead desorption from Lou soil as affected by different desorption agents

【目的】研究螯合剂和表面活性剂作用下污染土娄土中Cu、Pb的解吸动力学特征。【方法】在Cu单一污染、Pb单一污染和Cu、Pb复合污染土娄土中,分别加入2种螯合剂(乙二胺四乙酸(EDTA)、柠檬酸(CIT))和2种表面活性剂(十二烷基磺酸钠(SDS)、鼠李糖脂(RL2))作为解吸剂,采用批次试验方法,研究螯合剂和表面活性剂对污染土娄土中Cu、Pb不同形态及其含量的影响,并对其解吸动力学方程进行拟合。【结果】2种螯合剂对Cu、Pb的解吸是一个相对慢速的过程,240min左右时解吸基本达到平衡;而2种表面活性剂对Cu、Pb的解吸是一个相对快速的过程,在60min左右达到平衡。4种解吸剂对Cu的解吸量依次表现为EDTA>CIT>RL2>SDS;对Pb的解吸量依次表现为EDTA>CIT>SDS>RL2。【结论】4种解吸剂中,EDTA对污染土娄土中Cu、Pb的解吸效果最好;准二级方程能较好地描述4种解吸剂解吸污染土娄土中Cu、Pb的动力学特征。

【Objective】 The paper studied the desorption kinetics of Cu,Pb from contaminated soils by chelating agent and surfactant.【Method】 Two kinds of chelating agents（ethylenedinitrilo-tetraacetic acid disodium salt（EDTA）,citric acid（CIT）） and two surfactants（sodium dodecyl sulfate（SDS） and rhamnolipid（RL2）） were added in single Cu,Pb contaminated soil and mixed Cu and Pb contaminated soil.Batch desorption tests were performed to study the effect of the content and different forms of Cu and Pb which were desporpted by chelating agent and surfactant,and then fitted the desorption kinetics.【Result】 The results showed that the Cu and Pb desorption was a slow process with the two kinds of chelating agents treatments,and it took about 240 minutes to reach desorption equilibrium.In contrast,the Cu and Pb desorption was a rapid process with two surfactants treatment,and it took about 60 minutes to reach desorption equilibrium.The desorption amount of Cu followed the trend of EDTACITRL2SDS,the desorption amount of Pb followed the trend of EDTACITSDSRL2.【Conclusion】 The EDTA desorption of Cu,Pb in the contaminated Lou soil was the best among the four kinds of desorption agents;The pseudo-second-order equations well fit the experimental data.