以不同熟污泥配比改性黄土作为实验供试土壤，采用序批实验法研究了外源铅在0％、1％、2％、4％、6％、8％、10％、15％、20％、30％熟污泥质量配比的土壤样品中的吸附?解吸特征．结果表明：（1）不同熟污泥配比改性黄土对铅的吸附量随着Pb2＋平衡浓度的增加而增大，且在铅初始添加浓度小于25 mg·L－1时吸附量急剧增加．（2）在实验设定的浓度范围内（Pb2＋的初始添加浓度分别为0、5、10、25、50、100、200 mg·L－1），Henry模型、Langmuir模型、Freundlich模型对实验数据均有较好的拟合，但总体来看Freundlich型吸附等温方程是描述改性黄土对铅吸附的最佳模型．（3）在NH4AC作用下，改性黄土铅的解吸量随着吸附量的增加而增大．吸附量和解吸量之间的关系可以用线性方程很好地描述．当铅初始添加浓度小于25 mg·L－1时，Pb2＋的解吸率随着熟污泥配比的增加而增大，大于25 mg·L－1时，解吸率随着熟污泥配比增加而减小，且解吸率变化范围在0．11％—1．35％．（4）随着改性黄土中熟污泥含量的增加，不仅增加了改性黄土中有机质和全磷的含量，而且将会增强土壤对Pb2＋的吸附亲和力，降低了土壤中的铅对地下水造成二次污染的风险．
In this article, we adopted the laboratory batch experiments to test the sorption and desorption of lead in soils improved by 0%,1%,2%,4%,6%,8%,10%,15%,20%,30% composted sludge. The results revealed that:(1) The adsorption of lead in the tested soil increased with Pb2+concentration;and the adsorption increased dramatically with initial concentrations<25 mg·L-1.(2) Within the experimental concentration range Pb2+ adsorption was fitted well by Henry,Freundlich, and Langmuir equations, but it was best fitted by Freundlich.(3) Desorption of lead by NH4AC increased with increasing sorption. A linear equation well described the relationship between desorption and sorption. The desorption rate of lead increased with the proportion of composted sludge when the initial concentration of Pb2+ was < 25 mg·L-1, however when the initial concentration was > 25 mg·L-1 , the desorption rate of lead decreased with the proportion of composted sludge,and it was in the range of 0.11%—1.35%.(4)As the composted sludge in the tested soil increased, it not only increased organic matter and total phosphorous content, but also strengthened the adsorption affinity of Pb2+,and reduced the risk of secondary contamination of Pb2+to underground water.
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