高镁胶磷矿对重金属污染土壤的钝化修复

Passivation Repair of Heavy Metal Contaminated Soil by High Magnesium Phosphate Rock

通过室内培养试验,采取DTPA提取法研究了高镁胶磷矿在土壤中对重金属Cd、Pb的钝化作用。结果表明,高镁胶磷矿的施入显著降低了土壤重金属Cd、Pb的有效态含量,而且土壤中的Pb和Cd有效态含量与高镁胶磷矿的施入量呈显著负相关,由此说明高镁胶磷矿可降低重金属在土壤中的生物有效性和迁移性,从而达到修复重金属污染土地的目的;同一混施浓度下,高镁胶磷矿对重金属Pb的钝化效果相当于羟基磷灰石(HAP)(P>0.05),而对于重金属Cd而言,HAP钝化效果强于高镁胶磷矿,8%高镁胶磷矿对重金属Cd的钝化效果与4%HAP基本持平(P>0.05)。通过综合考虑钝化剂的来源、经济成本以及中国可利用磷矿资源缺乏等多方面因素,在重金属污染土壤修复的实际应用中,胶磷矿作为磷灰石的替代品具有一定的经济和研究意义。

The laboratory experiment was carried out to study the passivation repair of heavy metal Cd and Pb in the soil by high magnesium phosphate rock using DTPA extraction. The results showed that the application of high magnesium phosphate rock significantly reduced the available content of Cd and Pb in the soil. Besides,the contents of Pb and Cd in soil were negatively correlated with the application of phosphate rock,which indicated that phosphate rock could reduce the bioavailabil-ity and migration of heavy metals in the soil,so as to achieve the purpose of repairing heavy metal contaminated land. Under the same mixed fertilizer concentration,the passivation effect of phosphate rock on heavy metal Pb was equivalent to HAP （P 〉0.05）,-hereas for the heavy metal Cd, the effect of HAP passivation was stronger than phosphate rock,and 8% of phos-phate rock was basically the same as that of 4% of HAP （P 〉0.05）. Taking the source of the passivating agent, the economic cost and the lack of available phosphate rock resources in China into comprehensive consideration,the phosphate rock as a substitute for apatite has economic and research significance to some extent in the practical application of heavy metal con-taminated soil remediation.