水泥—磷尾渣复合材料修复铅、镉污染土壤的再溶出特性研究

The leaching properties of Pb and Cd contaminated soils solidified/stabilized by ordinary portland cement and waste phosphorus slag

为了解决Pb、Cd污染土壤修复难的问题,选用水泥—磷尾渣对Pb、Cd污染土壤进行修复处理.利用短期溶出试验(醋酸溶出法、硫酸—硝酸溶出法)和长期溶出试验(半动态溶出试验)评估了水泥—磷尾渣修复后Pb、Cd污染土壤的再溶出特性.结果表明:水泥—磷尾渣对Pb、Cd有极好的固定效果,可大幅度降低污染土壤中Pb、Cd的溶出特性.醋酸溶出试验和硫酸—硝酸溶出试验结果表明水泥—磷尾渣修复后污染土壤具有较强的耐侵蚀能力,且当水泥—磷尾渣组分比为9.4∶0.6时,Pb、Cd的醋酸溶出浓度和硫酸—硝酸溶出浓度均低于我国地表水Ⅴ类标准值,当水泥—磷尾渣组分比为9∶1时,Pb、Cd的醋酸溶出浓度和硫酸—硝酸溶出浓度均低于我国地表水Ⅱ类标准值.半动态溶出试验结果表明:水泥—磷尾渣修复后污染土壤Pb、Cd长期溶出风险较低,在半动态试验周期内Pb、Cd最大溶出浓度均低于我国地表水Ⅳ类标准值.水泥修复Pb、Cd污染土壤具备进行二次利用的潜力.

In order to solve the badly effect in solidified/stabilized Pb and Cd contaminated soils,the ordinary portland cement and waste phosphorus slag were used to solidified/stabilized Pb and Cd contaminated soils.The short-term leaching test(such as acetic acid leaching test and sulfur-nitric acid leaching test)and long-term leaching test(semi-dynamic leaching test)were used to investigate the leaching properties of cement and waste phosphorus slag treated Pb and Cd contaminated soils.The results showed that cement and waste phosphorus slag had an efficient effect on highly concentrated contaminated soils and leaching concentration decreased significantly.Acetic acid and sulfur-nitric acid leaching test results showed that the Pb and Cd contaminated soils treated by cement and waste phosphorus slag had highly eroding resistion.When the cement and waste phosphorus slag ratio was 9.4/0.6,the acetic acid and sulfur-nitric acid leaching concentration of Pb,Cd were below the environmental quality standards for surface water ofⅤcategory.When the cement and waste phosphorus slag ratio was 9/1,the acetic acid and sulfur-nitric acid leaching concentration of Pb,Cd were below the environmental quality standards for surface water ofⅡcategory.The semi-dynamic leaching test results showed that the Pb and Cd contaminated soils treated by cement and waste phosphorus slag had low environmental risk.The Pb and Cd leaching concentration of semi-dynamic leaching test were below the environmental quality standards for surface water ofⅣcategory.The Pb and Cd contaminated soils treated by cement and waste phosphorus slag had Pb and Cd contaminated soils treated by cement and waste phosphorus slag had highly reuse potential.