钙影响磷稳定土壤铅的机理研究

项目名称： 钙影响磷稳定土壤铅的机理研究

项目编号： No.41471253

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 李立平

作者单位： 河南工业大学

项目金额： 90万元

中文摘要： 大量研究表明，在铅污染土壤中添加磷酸盐是降低铅毒性和移动性的有效方法。磷酸盐可通过与铅直接沉淀或吸附-替代的方式形成磷-铅化合物。新近的研究表明，钙可促进磷酸盐对土壤铅的稳定。然而，钙影响磷酸盐稳定铅的机理尚不清楚。本项目通过溶液试验、悬液试验和土壤试验，探讨钙对磷稳定铅的影响及其机理。溶液试验通过反应探讨不同钙用量对铅和水溶态或难溶态磷反应及反应产物的影响；在悬液试验中，将土壤有机质或粘土矿物制成悬液，探讨悬液条件下钙用量对磷酸盐和铅反应及反应产物的影响。在土壤试验中，在铅污染土壤中加入磷和不同量的钙，探讨钙用量对磷、铅形态的影响。通过以上研究，尤其是通过利用同步辐射及XRD技术对反应中间产物的鉴别及结合钙在溶液和悬液体系中对磷稳定铅的影响及其机理、反应产物随时间的变化，最终阐明钙在土壤中影响磷酸盐稳定铅的机理。研究结果对于理解铅的土壤化学和更好利用磷酸盐稳定土壤铅有重要意义。

中文关键词： 重金属；铅；生物有效性；化学形态；化学修复

英文摘要： Numerous studies have proved that phosphate amendment can significantly reduce the toxicity and mobility of Pb in Pb-contaminated soils. Phosphates can form lead phosphates in Pb-contaminated soils by direct precipitation with Pb or sorption-substition reactions. Recent work indicated that calcium can enhance the immobilization of Pb with soluble phosphate in soil. However, the mechanism of such an enhancement is not clear yet. In this project, the mechnanism of Ca enhancing the immobilization of Pb in soil with phosphate amendment will be investigated by, i) solution experiment, in which calcium will be added at different amounts into a solution with phosphate and Pb, the effect o f calcium on the reaciton and the products will be analyzed, ii) suspension experiment, in which soil organic mattter and clay will be added into solutions to make suspensions, then phosphate, lead and calcium will be added into the mixture, the effect of calcium on the reaction and the species of the products will be analyzed, and by iii) soil incubation experiment, in which Pb-contaminted soil will be amended with phosphate and different amounts of calcium, and sampled at different times after amendment, the extractability of Pb, P and Ca will be analyzed, soil Pb species will also be analyzed with synchrotron methods. The results of above work, especially those of the Pb species during the incubation and those of solution and suspension experiment will elucidate the mechanism of the effect of calcium on the immobilization of Pb with phosphate in Pb-contaminated soils. The results will help the understanding of the geochemistry of Pb and better remediations of Pb-polluted soils.

英文关键词： Heavy metal;lead;bioavailability;species;chemical remediation