弱碱性矿粉对轻度Cu和Zn污染土壤的钝化修复试验研究

Experimental Immobilization of Copper and Zinc in Slightly Contaminated Soils with Alkalescent Mineral Powder

选用4种不同pH值的重金属污染土壤,通过室内模拟钝化试验,分别添加白云石、石灰石、硅灰石、磷矿粉4种矿粉,采用改进BCR法连续提取土壤中不同赋存形态的重金属,研究土壤中Cu和Zn赋存形态的变化,以获得不同矿粉对土壤中重金属的钝化特性。试验结果表明：白云石、石灰石、硅灰石、磷矿粉对土壤中Cu和Zn均有一定的钝化作用;多数情况下,白云石和石灰石对Cu污染的土壤钝化效果较好,在矿粉最高设计添加量2%（w/w）时,4种土壤中酸溶态Cu相对降低幅度为17.22%~50.49%,残渣态Cu相对升高幅度为3.24%~20.66%;石灰石和硅灰石对Zn污染的土壤钝化效果较好,在矿粉最高设计添加量2%（w/w）时,4种土壤中酸溶态Zn相对降低幅度为17.82%~28.48%,残渣态Zn相对升高幅度为5.98%~24.54%。

Through the simulated immobilization experiment in laboratory,this paper discusses the changes of Cu and Zn fractions in four kinds of heavy-metal contaminated soils with different pH values by adding four kinds of mineral powders,namely,dolomite,limestone,wollastonite and phosphate rock powder respectively. Then the paper evaluates the immobilization properties of heavy metals with four kinds of amendments by the modified BCR sequential extraction method. The results show that all the four kinds of mineral powders have positive effects on the immobilization of Cu and Zn in soils. In most cases, the immobilizing ability of dolomite and limestone on Cu in soils are better than that of the other two minerals. With the addition of the mineral powders being 2 % （w/w）, the acid- soluble fractions of Cu decreases by 17.22%-50.49% and the residual fractions of Cu increases by 3.24%-20.66 % compared with the control soils. The effect of limestone and wollastonite on immobilization of Zn is better than that of the other minerals. With the addition of the mineral powders being 2% （w/w）, the acid-soluble Zn fractions decreases by 17.82%-28.48% ,while the residual fractions of Zn increases by 5.98%-24.54%.