不同钝化剂对重金属污染土壤稳定化效应的研究

Immobilization Impact of Different Fixatives on Heavy Metals Contaminated Soil

利用腐殖质、硫酸铵、石灰、过磷酸钙及其复配组合对污染土壤中的重金属进行快速钝化处理,根据稳定效率和钝化剂的钝化能力Cap值对钝化材料进行筛选,并采用BCR形态分级实验(European Communities Bureau of Referent,欧共体标准测量与检测局提取法)研究钝化前后土壤中重金属的形态变化.结果表明:1在单一钝化材料实验中,2%石灰稳定效果最好;在复配实验中,以2%腐殖质+2%石灰稳定效果最好,Pb、Cu、Cd、Zn稳定效率分别达98.49%、99.40%、95.86%、99.21%.2钝化能力Cap值顺序:石灰>腐殖质+石灰>硫酸铵+石灰>磷肥>硫酸铵+磷肥>腐殖质+磷肥>腐殖质>硫酸铵.3BCR形态分级实验表明,腐殖质+石灰复合钝化剂对重金属的稳定化效应优于单一石灰处理.此外,当2%腐殖质先添加时Cd被活化,使Cd在随后加入的2%石灰处理下更容易转换为了稳定性较高的有机结合态和残渣态.

Four kinds of amendments including humus,ammonium sulfate,lime,superphosphate and their complex combination were added to rapid immobilize the heavy metals in contaminated soils. The best material was chosen according to the heavy metals' immobilization efficiency and the Capacity Values of the fixative in stabilizing soil heavy metals. The redistributions of heavy metals were determined by the European Communities Bureau of Referent( BCR) fraction distribution experiment before and after treatment.The results were as follows: 1In the single material treatment,lime worked best with the dosage of 2% compared to the control group.In the compound amendment treatments,2% humus combined with 2% lime worked best,and the immobilization efficiency of Pb,Cu,Cd,Zn reached 98. 49%,99. 40%,95. 86%,99. 21%,respectively. 2The order of Capacity Values was lime > humus + lime> ammonium sulfate + lime > superphosphate > ammonium sulfate + superphosphate > humus + superphosphate > humus >superphosphate. 3 BCR sequential extraction procedure results indicated that 2% humus combined with 2% lime treatment were very effective in immobilizing heavy metals,better than 2% lime treatment alone. Besides,Cd was activated firstly by 2% humus treatment then it could be easily changed into the organic fraction and residual fraction after the subsequent addition of 2% lime.