关键词: 凹凸棒土;温度改性;重金属;钝化

Abstract: 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℃,200℃,250℃,300℃,350℃,400℃,450℃and 0.5 h,1 h,1.5 h,2 h,2.5 h,3 h,4 h.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℃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%.

Key words: attapulgite;heat modified;heavy metal;immobilization