不同调控剂影响镉污染土壤浸出毒性的研究

采用美国TCLP标准的浸出方法,以海泡石、膨润土、石灰、钙镁磷肥、壳聚糖和草炭6种材料作为化学调控剂,模拟研究了各调控剂对镉污染土壤浸出毒性的调控效果,以期为镉污染土壤的化学修复提供理论依据及调控剂。结果显示,对镉含量为3.0mg/kg和6.0mg/kg的污染土壤而言,草炭和钙镁磷肥对酸性土壤镉的钝化效果最优,其钝化率最高分别达19.2%和38.4%;而钙镁磷肥对碱性土壤镉的钝化效果最好,其钝化率最高可达72.5%。对同一污染程度土壤,草炭和钙镁磷肥这两种调控剂对镉的钝化率均以碱性土壤优于酸性土壤。

Effect of Different Controlling Agents on Leaching Toxicity of Cadmium from Contaminated Soils

It has been identified as a cost-effective measure for soil remediation that chemical immobilization by adding controlling agents into heavy metals contaminated soils,and the key problem of that technique is to obtain some cheap and environment-friendly controlling agents.This simulation study indicated the effects of six chemical controlling agents,including sepiolite,bentonite,lime,calcium magnesium phosphate fertilizer,chitosan and peat,on leaching toxicity of cadmium from contaminated soils by the United States TCLP standard leaching method.The experiment results showed that,as to the passivation effects of contaminated soils whose cadmium content of 3.0 mg/kg or 6.0 mg/kg,the optimal agents for acid soil were peat and calcium magnesium phosphate fertilizer,with their maximum passivation rates were 19.2% and 38.4%,respectively.Moreover,the optimal agent for alkaline soil was calcium magnesium phosphate fertilizer,with their maximum passivation rate reached 72.5%.As to the contaminated soils on the same degree,the passivation rates of peat and calcium magnesium phosphate fertilizer in the alkaline soil was better than in the acidic soil.