不同钝化剂对铜污染土壤原位钝化修复

In-Situ-Immobilization by Different Passivators in Copper Contaminated Soils

考察了磷酸二氢钾、碳酸钙、硅酸钠、自制草木灰和自制生物质炭5种钝化剂对Cu污染土壤的钝化修复效果,对修复后的土壤进行了X射线衍射(XRD)分析;同时,对欧共体标准物质局提出的三步提取法(简称BCR法)进行了适当的改进,并运用改进的BCR法对Cu在土壤中的形态进行分析,以探讨不同钝化剂的作用机理。结果表明,5种钝化剂的投加量分别为50、100、20、20和20 g/kg时,对土壤钝化修复效果最佳,投加钝化剂后,土壤中可交换态Cu含量快速减少、残渣态Cu含量快速增加。其中,自制草木灰由于提高土壤p H更易与Cu生成沉淀,对Cu的钝化效果最佳,该钝化剂使有效态Cu含量减少53%,可交换态Cu含量减少49.2%,残渣态Cu含量增加4.7倍,有效地降低了Cu的生物毒性。

The effects of different modifiers, such as potassium dihydrogen phosphate, calcium carbonate, sodium silicate, homemade plant ash and homemade biochar on immobilization in copper contaminated soil were investigated respectively, and the immobilization mechanism was clarified through analyzing heavy metal fractions by using modified European Community Bureau of Reference （BCR） method and X-ray diffraction （XRD）. The results showed that the best dosing quantity （mass ratio） of the five modifiers was 50, 100, 20, 20, and 20 g/kg, respectively, and the amount of soluble Cu in soils decreased and residual Cu increased rapidly when modifiers were added in soils. Among them the plant ash made by ourselves which improved soil pH and generated precipitation with Cu was most effective to reduce Cu availability, the use of plant ash reduced the amounts of available and soluble Cu about 53% and 49.2% respectively, while increased residual Cu about 4.7 times of the original soils.