钝化剂种类对镉铅污染土壤的修复效果
Effects of different passivators on heavy metal contaminated soil
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摘要: 采用室内模拟培养的方式,研究油菜秸秆生物炭、重捕剂TMT、含氢硫基与硫化钠混合钝化剂在不同培养时间及不同添加量条件下对土壤中Cd、Pb含量及土壤理化性质的影响,以期筛选钝化效果较好的材料。试验结果显示:(1)3种钝化剂对土壤pH值的影响主要表现培养前15 d,培养后期pH值趋于稳定,重捕剂对土壤pH值提升了1.61个单位,效果最好。(2)3种钝化剂对Cd和Pb均有显著的钝化效果,其中混合钝化剂对有效态Cd和Pb的钝化效果最明显,钝化率分别达到44.9%和29.0%。(3)土壤有效态Cd、Pb含量与土壤pH值密切相关,呈负相关关系。(4)生物炭和重捕剂仅对土壤有机质、有效磷含量有显著的提升作用;而混合钝化剂对土壤有机质、碱解氮、有效磷和速效钾含量均有显著的提升作用,改善效果最佳。结果表明,混合钝化剂能显著降低污染土壤中有效态Cd和Pb含量,改善土壤各理化性质,修复钝化效果最好。Abstract:
Aiming to screen materials with better passivation effects, we used indoor simulated cultivation and studied the effects of rape straw biochar, capture agent TMT, mixed passivator containing sulfhydryl group and sodium sulfide on the contents of Cd and Pb in the soil as well as the physical and chemical properties of the soil under different cultivation times and dosages. The results showed: (1) The effects of the three passivating agents on the soil pH were mainly manifested in the early 15 days after the cultivation, while the pH tended to be stable at the later period. The capture agent increased the soil pH by 1.61 units, with the most effect. (2) The three passivating agents were with significant passivation effects on Cd and Pb. Among them, mixed passivator was with the most passivation effect on available Cd and Pb, with 44.9% and 29.0% of the passivation rates, respectively. (3) The contents of available Cd and Pb in soil were negatively correlated with soil pH. (4) Biochar and capture agent significantly improved soil organic matter and available phosphorus contents; while mixed passivator significantly increased the contents of soil organic matter, available nitrogen, available phosphorus and available potassium, with the most effect. The passivation agent mixed passivator significantly reduces the contents of available Cd and Pb in the contaminated soil and improves the soil physical and chemical properties, with the best passivation effect.