利用浸泡离心的方法,通过室内模拟实验,研究了浸泡时间、NaCl溶液浓度对土壤中6种重金属去除效果的影响,同时测定了NaCl浸泡前后土壤中重金属的形态变化.结果表明,浸泡时间为60d时达到最大去除率,分别为Cd30.3%、Zn22.0%、Pb9.4%、Cu8.0%、Cr12.6%、Ni9.9%;NaCl浓度为16g/L时达到最大去除率,分别为Cd41.9%、Zn19.9%、Pb9.3%、Cu6.3%、Cr14.8%、Ni16.8%.重金属形态分析显示,NaCl浸泡能有效去除交换态、碳酸盐结合态和氧化物结合态的重金属,而对有机态和残渣态的重金属作用效果不明显.
An experiment was conducted to remove heavy metals in reclaimed tidal flat soil from the Pearl River estuary by immersion in NaCl solution.The effects of immersion durations and NaCl concentrations on the removal of six heavy metals were examined.The chemical forms of heavy metals in soil before and after immersion were also determined.Removal rate of heavy metals was the maximum at 60d or NaCl 16g/L immersion,being 30.3% for Cd,9.4% for Pb,8.0% for Cu,22.0% for Zn,12.6% for Cr and 9.9% for Ni,and 41.9% for Cd,9.3% for Pb,6.3% for Cu,19.9% for Zn,14.8% for Cr and 16.8% for Ni,respectively.Speciation changes of heavy metals in the treated soil indicated that NaCl was effective in removing the exchangeable,carbonate and oxide forms of heavy metals,but ineffective for their organic and residual forms.