摘要
采用不同浓度的乙二胺四乙酸(EDTA)和柠檬酸(CA)混合的淋洗方法对重金属复合(Zn、Cu、Pb、Cr、Ni)污染土壤的最佳淋洗方式进行研究,探讨了pH值、液固比、淋洗时间和淋洗顺序对其淋洗效果的影响,并分析了0.08mol/L EDTA+0.4 mol/L CA混合淋洗处理前后土壤中重金属各种形态的变化。结果表明:采用0.08mol/L EDTA+0.4mol/L CA按复配体积比为5∶5混合淋洗对多种重金属污染土壤的淋洗效果最佳,且对土壤中5种重金属的去除率明显高于同等条件下单独使用CA和EDTA的淋洗效率,去除率分别为Zn 94.7%、Cu 95.0%、Pb 91.1%、Cr 53.8%、Ni 58.1%;采用0.08mol/L EDTA+0.4mol/L CA按复配体积比为5∶5混合淋洗,当混合淋洗液pH值为4.0、淋洗时间为14h、液固比为10∶1时,Cu、Pb、Zn、Ni、Cr的洗脱率分别为93.0%、85.3%、99.0%、50.5%、45.1%;采用0.08mol/L EDTA+0.4mol/L CA混合淋洗能很好地将土壤中重金属从稳定态向不稳定态转化,进而使得土壤中重金属得以去除。
This paper coins different concentrations of Citric acid(CA)and Ethylenediamine tetraacetic acid(EDTA)to determine the optimal mixing concentration on leaching heavy metals contaminated soil(Zn、Cu、Pb、Cr、Ni).Also,the paper investigates the effects of liquid-solid ratio,leaching time,and pH on leaching efficiency and analyzes the morphology before and after tested heavy metals are leached by the mixture of 0.08mol/L EDTA+0.4 mol/L CA.The results shows that the mixture of 0.08 mol/L EDTA+0.4mol/L CA could not only remove various heavy metals simultaneously but also be better than single CA or EDTA,with removal rates of Zn,Cu,Pb,Cr and Ni 94.7%,95.0%,91.1%,53.8% and 58.1%respectively.The mixture of 0.08mol/L EDTA+0.4mol/L CA could obtain the highest leaching efficiencies when pH is 4,leaching time is 14 hours,or liquid solid ration is 10∶1.The removal rates of Zn,Cu,Pb,Cr and Ni could reach 93.0%,85.3%,99.0%,50.5% and 45.1% respectively.Furthermore,the mixture of 0.08mol/L EDTA+0.4mol/L CA could well transfer the heavy metal from stable form to unstable form and end up with the removal of heavy meatal.
出处
《安全与环境工程》
CAS
2017年第3期77-83,共7页
Safety and Environmental Engineering
基金
武汉市高新技术成果转化及产业化专项项目(2013060803010403)
关键词
污染土壤
复合重金属
乙二胺四乙酸
柠檬酸
混合淋洗
淋洗条件
重金属形态
contaminated soil
combined heavy metal
Ethylenediamine tetraacetic acid(EDTA)
Citric acid(CA)
mixture leaching
leaching condition
heavy metal speciation