动电修复不同形态重金属污染土壤效果研究

以钢铁厂附近废地的重金属土壤为对象,研究了动电修复技术去除重金属效果与其各化学形态的关系,讨论了电能消耗。结果表明,同一种重金属,其动电去除效率顺序为交换态碳酸盐结合态Fe-Mn氧化结合态有机结合态残留态,即吸附性越弱的形态,其去除率越高,如交换态去除率95%;吸附性越强的形态,其去除率越低,如有机态和残留态去除率低于29%;对于不同重金属,高移动性和弱吸附性的重金属较弱移动性和强吸附性的重金属去除效果好,即各形态的Cd、Cu和Zn的去除率明显高于相应形态Pb的去除率;能耗分析表明,实验时间超过96 h后,在电能有较大消耗的同时,重金属去除率却提高不明显。

Study on electrokinetic remediation efficiencies of different fractions of heavy metals in soils

The research focused on the relationship between the removal effictiveness of heavy metals by the electrokinetics and the forms of heavy metal in soil near Longyan steel and iron works and analyzed the electric energy expenditures. The order of removal rates of heavy metals by electrokinetics in its different speciations was exchangeable fraction>carbonates >Fe/Mn oxides>organic/sulfides>residual fraction in the identical kind of heavy metals.The removal efficiencies of high mobile and weakly bound heavy metals were higher, such as the exchange fraction were more than 95% by electrokinetic treatment, but immobile and strongly bound fraction were not significantly removed, such as organic and residual fraction were less than 29% removal efficiencies.The removal efficiencies of Cd,Cu and Zn in their various forms were significantly higher than corresponding that of Pb. The results of energy consumption analysis indicated that the energy expenditures increased significantly, but the removal rates of the heavy metals elevated a little when the test time continued for more than 96 hours.