熟污泥改性黄土对Pb^(2+)的吸附解吸特征  

Sorption and desorption of Lead in loess improved by composted sludge

作　　者：周健[1] 金诚[1] 李晓林[1] 姚驯 南忠仁[1] 

机构地区：[1]兰州大学资源环境学院,兰州730000

出　　处：《环境化学》2015年第9期1710-1715,共6页Environmental Chemistry

基　　金：国家自然科学基金(51178209;91025015);兰州大学中央高校基本科研业务费专项资金(lzujbky-2015-214)资助

摘　　要：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 , 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.

关 键 词：熟污泥 黄土 铅 吸附 解吸 

分 类 号：X53[环境科学与工程—环境工程]