铁铝吸附剂对起爆药污染土壤中锑的稳定化研究

采用3种铁基吸附剂（FeSO₄•；7H₂O、针铁矿、Fe⁰）和铝基吸附剂（Al（OH）₃），对某起爆药污染场地土壤中锑（Sb）进行稳定化处理，通过等温吸附实验、批量浸出实验、比表面积测定以及BCR分析，研究了铁、铝单一和混合吸附剂的稳定化效果以及稳定化前后土壤比表面积及Sb形态的变化.结果表明：不同铁基吸附剂对Sb的等温吸附符合Freundlich模型，FeSO₄ （log K_f= 5.85）的吸附能力明显高于Fe⁰ （log K_f = 3.21）和针铁矿（log K_f = 4.32）；稳定时间为10d的条件下，不同铁基吸附剂对Sb的稳定化效率随添加量的增大而提高，且10%FeSO₄（97.1%） > 10% Fe⁰（72.3%） > 针铁矿（41.0%）；FeSO₄的添加明显促进了土壤中Zn、Cu、Pb的浸出，达到原土壤浸出浓度的1990.2、2.8倍和21.6倍，添加Al（OH）₃后能够显著降低Zn、Cu、Pb的浸出浓度，添加量为4%时，稳定化效率分别达到93.8%（Zn）、93.5%（Cu）和98.3%（Pb）；5%FeSO₄和4% Al（OH）₃混合吸附剂对Sb及Zn、Cu、Pb的综合稳定化效率最好，处理10d后稳定化效率最高可达94.6%、74.2%、82.2%和97.6%；进一步分析表明，混合吸附剂添加后比表面积能够达到原土壤的1.31~1.67倍，残渣态Sb比例增加0.037~0.197倍，与稳定化效果相一致，表明铁铝混合吸附剂是处理起爆药污染场地复合重金属污染土壤的有效途径.

Study on stabilization of antimony (Sb) in contaminated soil by primary explosives using iron-based and aluminum-based adsorbents

Iron-based (ferrous sulfate, goethite and iron powder) and aluminum-based (aluminum hydroxide powder) adsorbents were amended to stabilize antimony (Sb) in primary explosives contaminated soils. The stabilizing effects of iron-based adsorbent, aluminum-based adsorbent, and iron-aluminum mixed adsorbent, as well as the changes of specific surface area and the transformation of Sb after stabilization were investigated by sorption isotherm experiments, batch leaching experiments, specific surface area determination and European Community Bureau of Reference (BCR) analysis. Results showed that the isothermal sorption of different iron-based adsorbents for Sb were well described by the Freundlich equation, and the sorption capacity of FeSO₄(log K_f = 5.85) was significantly higher than Fe⁰ (log K_f = 3.21) and goethite (log K_f = 4.32). After 10days, the stabilization efficiency of different iron-based adsorbents for Sb increased with addition, and 10% FeSO₄ (97.1%) > 10% Fe⁰ (72.3%) > goethite (41.0 %). The concentrations of Zn, Cu and Pb in leachates from the soils amended by FeSO₄ were 1990.2, 2.8 and 21.6 times higher than control respectively, and it also decreased significantly by aluminum hydroxide amendments. With 4 % addition of aluminum hydroxide, the stabilization efficiencies for Zn, Cu, and Pb was 93.8%、93.5% and 98.3%, respectively. The mixture of 5% FeSO₄ sulfate and 4% aluminum hydroxide had the best stabilization effect on Sb, Zn, Cu, and Pb in soil, and the maximum stabilization efficiencies were 94.6%、74.2%、82.2% and 97.6% respectively after 10days. Further analysis revealed that, the specific surface area could reach 1.31~1.67 times that of the original soils and the residual fraction of Sb also increased by 0.037~0.197 times after adding the iron-aluminum mixed adsorbents, which was consistent with the stabilization effect. Our results indicated that using iron-aluminum mixed adsorbent is an effective way to stabilize heavy metals combined contaminated soils.