含铁材料和稀土材料对矿区土壤As的固定效果

Effects on Immobilization of Arsenic in Mining Area Soil by Iron-containing Materials and Rare-earth Materials

通过分析添加含铁材料(Fe2O3、Fe2(SO4)3)和稀土材料(CeCl3、LaCl3)后矿区污染土壤中交换态砷(As)含量和土壤pH值的变化规律,研究这2类材料对矿区土壤As的固定效果以及对土壤性质的影响。结果表明,Fe2O3对As固定效果不明显,当Fe2O3最大添加量为8g/kg(分别按Fe计)时,土壤中交换态As含量仅降低了3.81%,其他3种材料在本试验条件下表现出良好的效果,其中Fe2(SO4)3和LaCl3固定As的效果相当,CeCl3次之。当这3种材料的添加量分别为2,4,8g/kg(按Fe、La、Ce计)时,土壤交换态As含量无法检出。对土壤pH的测定发现,Fe2O3对土壤pH几乎没有影响,其他3种材料都不同程度降低了土壤pH,Fe2(SO4)3对土壤的酸化尤为明显,CeCl3和LaCl3对土壤的酸化强度相当。

An incubation experiment was conducted to study immobilization of arsenic in mining area soil by two kinds of material,namely,iron-containing materials（Fe2O3,Fe2（SO4）3） and rare-earth materials（CeCl3,LaCl3）.The results showed that Fe2O3 had little effect on immobilization of soil arsenic,attaining only 3.81% decrease in exchangeable arsenic at an application of 8 g/kg（Fe）.On the contrary,the other three materials proved to be effective in immobilizing arsenic.Fe2（SO4）3 was the most effective as well as LaCl3,followed by CeCl3.When the addition amount was 2,4,8 g/kg（Fe,La,Ce,respectively）,exchangeable arsenic could not be detected.Data of soil pH indicated that Fe2O3 had little influence on soil pH,however others acidize the soil,especially Fe2（SO4）3 which resulted in acidification of soil seriously,and two rare-earth materials had almost the same ability of acidification.