两种改良剂对矿区重金属污染土壤中Pb、Cd、Zn的固定效果

摘要

The fixing effects of Pb, Cd, Zn in polluted mining soil of Shizhuyuan mining areaXhenzhou city were studied by applying two modifying agents, L e. , bentonite and calcium dihydrogen phosphate to the soil with heavy metals. The results show that (l)Both bentonite and calcium dihydrogen phosphate increased the contents of exchangeable Pb and Cd in soil, and they had little influence on the content of exchangeable Za (2)The contents of exchangeable Pb reduced at first with the increase in amount of bentonite, when the amount of bentonite was 2. 0 g . Kg-1, the content of exchangeable Pb had a maximum decrement of 0. 48%, and then it increased again. Meanwhile, the contents of exchangeable Cd and Zn kept reducing and the maximum decrements were 7. 75% and 0. 41%. (3) Application of calcium dihydrogen phosphate to the polluted soil reduced contents of exchangeable Pb and Cd, when the amount of calcium dihydrogen phosphate was 4. 0 g. kg-1, the content of exchangeable Pb had a maximum decrement of 1. 31%, and when the amount of calcium dihydrogen phosphate was 1. 0 g . Kg-1, exchangeable Cd had a maximum decrement of 7. 99%. As application of calcium dihydrogen phosphate to the polluted soil, the content of exchangeable Zn increased, leading a disadvantage to Zn fixing. (4)Calcium dihydrogen phosphate was superior to bentonite in fixing Pb, Cd and Zn.%对重金属污染土壤分别施加膨润土和磷酸二氢钙2种改良剂，研究了这两种改良剂对土壤中Pb、Cd、Zn的固定效果。实验结果表明：(1)膨润土和磷酸二氢钙均可以降低土壤中交换态Pb、Cd的含量，对交换态Zn含量的影响不明显。(2)随着膨润土的加入量的增加，交换态Pb含量先减少，当施人量为2.0 g·kg-1时，其减少量最大，减少了0.48％，随后交换态Pb含量又呈增高趋势；而交换态Cd、Zn的含量则呈降低趋势，最大减少量分别为7.75％、0.41％。(3)随着磷酸二氢钙施加量的增加，交换态Pb、Cd含量均有明显的降低，且都呈现先减少而后逐渐上升的趋势。当加入4.0 g·kg-1时，交换态Pb减少量最大，减少量为1.31％；当加入1.0 g·k-1时，交换态Cd含量减少最大，减少了7.99％。而加入的磷酸二氢钙使交换态Zn量增加了，因此磷酸二氢钙不利于Zn的固定。(4)磷酸二氢钙对Cd、Pb的固定效果优于膨润土。