不同环境材料对Pb、Cd污染土壤的淋溶效应

Leaching effects of different environmental materials on soils polluted by Pb and Cd

为了探索环境材料对土壤中重金属的去除效果,采用土柱淋溶方法研究了不同环境材料(腐殖酸HA、高分子材料SAP、粉煤灰FM及沸石FS)对污染土壤(单一Pb污染土壤、单一Cd污染土壤和Pb-Cd复合污染土壤)中铅(Pb)、镉(Cd)的淋溶效应.结果表明:添加不同环境材料处理的淋出液pH值呈现先上升后降低再上升的趋势,均为弱碱性.添加FM和复合N1(HA+SAP+FM+FS)、N2(HA+SAP+FM)处理淋出液的电导率(EC)明显高于其它.FM和复合N1、N2对单一Pb污染土壤中Pb达到显著固定作用;单一Cd污染土壤中,添加单一SAP处理所淋溶出的Cd量小于CK(未加任何环境材料),淋溶出的Cd量为CK的63.68%,对Cd起到一定的固定作用;Pd-Cd复合污染土壤中,HA对Pb达到显著固定作用,淋出Pb量仅为CK的40.6%.SAP及复合N3对Cd的固定作用明显,淋溶出的Cd量分别为CK的55.32%、78.13%.可见,采用的环境材料对重金属淋溶能起到一定的抑制作用.

In order to investigate the removal efficiency of heavy metals in soil by environmental materials,the leaching effect of different environmental materials,humic acid（HA）,polymer materials（SAP）,fly ash（FM） and zeolite（FS）,on soil polluted by Pb and Cd was measured by soil column leaching.The results showed that the pH values of the soil leaching first increasing and then decreasing and rising again,were alkaline in the above environmental media.The electricity conductivity（EC） of the soil leaching treated by fly ash and complex environmental media N1（HA＋SAP＋FM＋FS）and N2（HA＋SAP＋FM）,was obviously higher than that of the soil leaching treated by other environmental materials.For the soil polluted by Pb,the fixation of Pb in environmental media,such as fly ash and N1,N2 was higher than that of Pb in check environmental media;By comparison,for the soil polluted by Cd,the fixation of Cd in polymer materials was higher than that of Cd in other check environmental materials.In the soil contaminated by Pb and Cd,the fixation of Pb by humic acid was higher than that of Pb by check material,and compared with check material,the Pb release quantity treated by HA was 40.6% of it.And the fixation of Cd by polymer materials and N3（HA＋SAP＋FS） was higher than that of Cd by check material,and compared with check leaching,the Cd concentration of leaching reached to 55.32% and 78.13% respectively.Therefore,it indicated that the environmental materials played an inhibitory effect on leaching of heavy metals.