铁锰氧化物与膨润土对锑-砷复合污染土壤的稳定化研究

通过室内土培实验，以Fe-Mn氧化物和膨润土为稳定化材料，研究材料配比、使用量同时稳定As和Sb的效果；结合稳定时间和形态分析，探讨材料的长效稳定性及作用机制。结果表明，Fe-Mn氧化物∶膨润土=4∶1的处理具有很好的稳定As和Sb的效果；当使用量为3%时，Sb和As水浸出降低率为55%和97%；随着时间的延长，As的稳定化效果未出现明显变化，而Sb的稳定化效果有所降低。形态分析结果表明，3%使用量的Fe-Mn氧化物∶膨润土=4∶1的处理使土壤中As和Sb由可交换态向残渣态转变，稳定性增强；Fe-Mn氧化物微观结构特征表明，其具有的较大比表面积和较强的氧化还原能力对As、Sb的稳定起了重要作用。因此，Fe-Mn氧化物和膨润土的优化使用，能修复As、Sb复合污染土壤。

Stabilization Effect of Fe-Mn Binary Oxides and Bentonite on Antimony-arsenic Co-contaminated Soils

This study carried out laboratory culture experiments to investigate effects and mechanisms of Fe-Mn binary oxides and bentonite to stabilize As and Sb in contaminated soils. Results showed that the amendment of Fe-Mn binary oxides: bentonite=4:1 stabilized As and Sb in soils significantly by reducing respectively 97% and 55% of their water-leachable contents when applied dosage was set as 3%. The stabilization of Sb was found decreasing gradually, while As in soil showed a long-term stabilization. The Tessier sequential extraction test showed that 3% dosage of amendment in soils made acid exchangeable As and Sb transforming into the residual fractions. The microscopic characterization of Fe-Mn binary oxide indicated that the stabilization ability of amendment to As and Sb resulted mainly from the large specific surface area and the strong redox ability. In conclusion, optimized use of Fe-Mn binary oxides and bentonite can be an effective stabilization agent to remediate As and Sb co-contaminated soils.