磷酸盐对污染土壤中Pb·Cd·Zn的钝化效果

Inactivation Effect of Phosphate on Pb,Cd and Zn in Contaminated Soil

[目的]研究磷酸盐对重金属Pb、Cd、Zn的钝化作用。[方法]以磷酸盐作为钝化剂,添加量设为50~1 200 g/m^2,考察Pb、Cd、Zn的有效态浓度随着钝化剂添加量的变化。[结果]随着磷酸盐添加量的增大,Pb、Cd、Zn有效态浓度均呈下降趋势,Pb从280 mg/kg下降到123 mg/kg,Zn从14.20 mg/kg下降到7.18 mg/kg,Cd从1.50 mg/kg下降到1.27 mg/kg,最终得到最佳添加量为500 g/m^2,并且30 d后Pb、Cd、Zn有效态浓度达到稳定状态。添加磷酸盐后土壤pH从5.62增加到7.57。[结论]磷酸盐可使土壤中的Pb、Cd、Zn浓度明显降低,达到预期的土壤修复效果。

[ Objective] To study the inactivation effect of Pb, Cd and Zn by heavy metal phosphate. [ Method] The effective concentration of Pb, Cd and Zn was determined by using 50 - 1 200 g/m^2 as a passivating agent. [ Result]The results showed that effective concentrations of Pb, Cd and Zn decreased with the increase of the passivation dose, the Pb decreased from 280 mg/kg to 123 mg/kg, Zn decreased from 14.20 mg/kg to 7.18 mg/kg, the Cd decreased from 1.50 mg/kg to 1.27 mg/kg, and finally the optimal addition amount was 500 g/m^2. After 30 days, the effective concentration of Pb, Cd, Zn reached a stable state. After adding the passivator, the pH of the soil was increased from 5.62 to 7.57. [ Conclusion ] The Pb, Cd and Zn concentrations in the soil can be reduced significantly by the phosphate passivation agent, which can achieve the desired effect of soil remediation.