Extraction of heavy metals from water-stable soil aggregates using EDTA
Surface soil samples (0-15cm) were collected from a lead/zinc tailing site in Nanjing,China,and separated into four size fractions of water-stable aggregates.Metal contents in the bulk soil were 7479±370 mg·kg-1 for Zn,4189±82mg·kg-1 for Pb,58.0±0.4 mg·kg-1 for Cd and 544±22mg·kg-1 for Cu,respectively.Contents of Zn,Pb,Cd and Cu in 0.02-0.002 mm fractions were lower than them in other size fractions.Extraction of heavy metals from each size fractions of aggregates as function of extraction time and pH value of EDTA was performed.Also,the effects of the extraction process on metal fractions in the samples were investigated.The molar ratio of EDTA/total heavy metals (Zn+Pb+Cu+Cd) was adopted as 1 for all extraction experiments.The extraction kinetics of the four metals in each fraction could be well fitted with Elovich formula.Pb had the highest extraction efficiency at time 24h,82.7% (2-0.2 mm),73.6% (0.2-0.02 mm),75.0% (0.02-0.002),and 72.2% (<0.002 mm),among the four tested metals.The highest desorption rate for four metals in different size fractions was Zn in <0.002 mm fraction and Pb,Cd,and Cu in 2-0.2 mm fraction.Extraction of the tested metals negatively depended on the original pH value of extraction solution and the relationship could be described linearly.Exchangeable/acid soluble Zn,exchangeable/acid soluble and reducible fraction ofPb,Cd and Cu were influenced greatly by the extraction using EDTA.
Soil aggregates heavy metal tailing soil EDTA extraction
Zhuhong Ding Quyi Wang Xin Hu
School of Environment, Nanjing University of Technology, Nanfing 211816, China Center of Material Analyses, Nanjing University, Nanjing 210093,.China
国际会议
2013 International Symposium on Environmental Science and Technology(2013环境科学与技术国际会议)
大连
英文
549-553
2013-06-04（万方平台首次上网日期，不代表论文的发表时间）