不同钝化剂对污染土壤中多重金属的固定

摘要

The effects of 4 passivators, zeolite, lime, red mud and peanut shell biochar, on the fixation of Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils were studied by passivator culture experiment in order to screen out the passivator with better fixation effects. The results showed that the soil pH values of zeolite, lime, red mud and peanut shell biochar increased significantly by 0.51～1.02, 0.82～1.29, 0.72～0.89 and 0.30～0.35 respectively. The effects of 4 passivators on the fixation of Cd and Zn in soil are lime>red mud>zeolite>peanut shell biochar. The order of effects on the fixation of Pb is red mud>lime>zeolite>peanut shell biochar. The order of the fixation effects of Cu is red mud>lime>peanut shell carbon>zeolite. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 decreased with the increase in the dosage of 4 passivators. Lime and red mud showed good fixation effects on Cd, Pb, Cu and Zn. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 at the low dosage (2.5 g/kg) of lime and red mud decreased by 41％, 84％, 76％ and 83％ respectively. Soil pH value was negatively correlated with CaCl2-Cd, Pb, Cu and Zn (P<0.01). Lime and red mud had significant fixation effects on Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils at low application dosages.%采用钝化剂培养试验,研究施加沸石、石灰、赤泥和花生壳炭4种钝化剂对酸性多重金属污染土壤Cd、Pb、Cu和Zn的固化效果,以期筛选出对其固定效果较好的钝化剂.结果表明:施用沸石、石灰、赤泥和花生壳炭土壤pH值分别显著升高0.51～1.02、0.82～1.29、0.72～0.89和0.30～0.35;4种钝化剂对土壤中Cd和Zn固化效果的影响依次为石灰>赤泥>沸石>花生壳炭,Pb固化效果的影响依次为赤泥>石灰>沸石>花生壳炭,对Cu固化效果的影响依次为赤泥>石灰>花生壳炭>沸石;土壤CaCl2提取态Cd、Pb、Cu和Zn含量随着4种钝化剂施用量的增加而降低,石灰和赤泥对Cd、Pb、Cu和Zn均有较好的固定效果,施加低量(2.5 g/kg)石灰和赤泥土壤CaCl2提取态Cd、Pb、Cu和Zn含量降低程度分别在41％、84％、76％和83％ 以上.可知,土壤pH值与CaCl2提取态Cd、Pb、Cu和Zn含量均呈显著负相关(P<0.01),石灰和赤泥在低施用量时对酸性多重金属污染土壤Cd、Pb、Cu和Zn具有的固定效果.