凹凸棒基土壤重金属钝化材料的热改性制备方法及功能研究

Function and Heat Modification of Immobilization Materials Made by Attapulgite for Heavy Metals in Soil

为探讨不同煅烧温度和煅烧时间下的凹凸棒土对土壤中重金属的钝化效果,将10目的凹凸棒土颗粒,在150℃、200℃、250℃、300℃、350℃、400℃、450℃条件下,分别改性0.5 h、1 h、1.5 h、2 h、2.5 h、3 h和4 h,通过钝化人工配制的重金属污染土壤中Cu和Zn来判断其钝化效果。结果表明:较低温度(<350℃)对凹凸棒土的钝化容量影响较小,当改性温度为350℃和400℃时,凹凸棒土的钝化容量提高最显著,改性温度大于400℃时,凹凸棒土的钝化容量开始降低,凹凸棒土在400℃下高温煅烧1.0~1.5 h时对土壤中Cu和Zn的钝化容量最大。分别向土壤中添加400℃下高温煅烧1.0 h和1.5 h的凹凸棒土能显著降低玉米植株中重金属Cu和Zn的富集量,与对照组相比分别减少了34.76%和57.56%。

In order to investigate the passivation effect of attapulgite calcinated by different calcination time and calcination temperature on different heavy metals in the soil,10 mesh(1.7 mm)of the attapulgite particles was calcinated respectively under condition of 150 Tl,200℃,250℃,300℃,350℃,400℃,450℃and 0.5h,lh,1.5h,2h,2.5h,3h,4h.The passivation effect was simulated by passivating Cu(800 mg/kg),Zn(800 mg/kg)in contaminated soil.The results show that lower temperature(less than 350)has little significant effect on the passivation capacity of attapulgite.The passivation capacity of attapulgite is improved significantly when the modification temperature is 350℃and 400℃.When the temperature is higher than 400℃,the capacity of the attapulgite is reduced.Calcinated at 400℃for 1.0 h to 1.5 h,the passivation capacity of attapulgite to Cu and Zn in soil come to the highest level.The content of Cu,Zn in maize plants could be significantly reduced by adding the passivation agent,and which is decreased gradually with the increase of passivation capacity.Calcinated with the control group,adding the attapulgite calcined at 400 Tl for 1.0 h and 1.5 h into soil respectively could significantly reduce the enrichment of Cu and Zn in maize plants by 34.76%and 57.56%.