CaO与NaH_(2)PO_(4)对陈腐垃圾腐殖土中Zn和Cd的钝化效果

Passivation effect of CaO and NaH_(2)PO_(4) on Zn and Cd in humus soil

防治陈腐垃圾腐殖土的重金属污染对陈腐垃圾腐殖土资源化利用具有重要意义.本研究以CaO和NaH_(2)PO_(4)作为钝化剂,设置CK、5%CaO、10%CaO、5%NaH_(2)PO_(4)和10%NaH_(2)PO_(4)的处理开展钝化试验和土柱淋溶试验,探究CaO和NaH_(2)PO_(4)对陈腐垃圾腐殖土中Zn和Cd迁移性及形态的影响.结果表明,淋溶试验中,5%CaO和5%NaH_(2)PO_(4)处理Zn的累计释放量分别比对照减少了88.71%和50.29%,Cd的累计释放量分别较对照减少了97.06%和59.38%;10%CaO和5%NaH_(2)PO_(4)处理对陈腐垃圾腐殖土Zn中钝化效果最好,使腐殖土中有效态Zn分别减少了93.5%和37.9%;施用CaO和NaH_(2)PO_(4)两种钝化剂改变了陈腐垃圾腐殖土中官能团的结构,部分官能团与Zn和Cd结合形成稳定化合物,使活性态Zn和Cd向稳定态转化,能有效防治腐殖土中Zn和Cd对环境的潜在危害.CaO是钝化陈腐垃圾腐殖土中Zn和Cd的优良钝化剂,但不同环境下CaO的使用量及施用CaO对植被的影响有待进一步深入探讨.

Preventing heavy metal pollution in humus soil is of great significance to the utilization of humus soil.In this study,CaO and NaH_(2)PO_(4) were used as passivating agents,and the treatment of CK,5%CaO,10%CaO,5%NaH_(2)PO_(4) and 10%NaH_(2)PO_(4) were set to carry out passivation experiments and soil column leaching experiments,to explore the effects on the mobility and morphology of Zn and Cd in humus soil.The results showed that in the leaching experiment,the cumulative release of Zn treated with 5%CaO and 5%NaH_(2)PO_(4) decreased by 88.71%and 50.29%,respectively,and the cumulative release of Cd decreased by 97.06%and 59.38%.The 10%CaO and 5%NaH_(2)PO_(4) treatments had the best passivation effect on the Zn in the humus soil,reducing the available Zn in the humus soil by 93.5%and 37.9%,respectively.The application of CaO and NaH_(2)PO_(4) two passivating agents changed the structure of functional groups in humus soil.Some functional groups combined with Zn and Cd to form stable compounds,which transformed the active state of Zn and Cd to a stable state and can effectively prevent the potential harm of Zn and Cd in humus soil to the environment.CaO is an excellent passivator to passivate Zn and Cd in humus soil.However,the amount of Cao used in different environments and the effect of CaO application on vegetation need to be further studied.