ABSTRACT

Exploring an economic and efficient method for simultaneous passivation of As and Cd in soils is of great current significance. In this study, a low-cost composite material, Fe₂O₃-vermiculite (Fe-V), for effectively passivating As/Cd was synthesized successfully based on hydrophobic aggregation method. The reaction products were characterized by XRD, SEM, EDS and FTIR, results showed that Fe₂O₃ was successfully loaded onto the surface of vermiculite by the connection with sodium stearate and employed this composite material to passivate the co-contaminated soil with As/Cd. All the percentage of toxicity reduction (P_d value) was higher than the control group, which indicated the passivation was effective. In soil A (As 45 mg/kg and Cd 6 mg/kg), the P_d of As were higher than 90%, the P_d of Cd were 80–100%. And in soil B (As 80 mg/kg and Cd 10 mg/kg), the P_d of As were more than 84.68%, the P_ds of Cd were about 99%. In the meantime, the application of Fe-V could apparently increase the residual fraction of As and Cd in soil A and soil B. Moreover, the passivation of As and Cd in soils by Fe-V composite materials was a combined physical and chemical action system. This research shows that Fe-V could play a good role in the passivation of As/Cd in different pollution levels of soils.

摘要

探索一种经济高效的同时钝化土壤中As和Cd的方法具有重要的现实意义。本研究基于疏水聚集法成功合成了一种用于有效钝化As/Cd的低成本复合材料Fe ₂ O _{3 -蛭石(Fe-V)。}对反应产物进行XRD、SEM、EDS和FTIR表征，结果表明Fe ₂ O ₃通过与硬脂酸钠的连接成功负载到蛭石表面，并采用该复合材料对As/光盘。所有毒性降低百分比（P _d值）高于对照组，表明钝化是有效的。在土壤 A（As 45 mg/kg 和 Cd 6 mg/kg）中，As 的 P _d高于 90%，Cd 的 P _d为 80-100%。而在土壤B（As 80 mg/kg和Cd 10 mg/kg）中，As的P _d大于84.68%，Cd的P _d约为99%。同时，Fe-V的施用可以明显增加土壤A和土壤B中As和Cd的残留率。另外，Fe-V复合材料对土壤中As和Cd的钝化是物理和化学的综合作用。系统。本研究表明，Fe-V在不同污染程度的土壤中对As/Cd的钝化具有良好的作用。