不同稳定剂对污染沉积物中重金属的稳定效果

采用壳聚糖、单宁酸和羟基磷灰石对沉积物中的重金属进行稳定化处理,并运用毒性浸出方法(TCLP)和重金属形态变化来评价其稳定效果.结果表明:壳聚糖、单宁酸及羟基磷灰石对于沉积物中重金属具有明显的稳定效果,羟基磷灰石对4种重金属Pb、Cu、Zn和Cd的稳定效率最高,分别达到90.03%、80.46%、60.40%和79.23%,单宁酸次之,壳聚糖对Zn的稳定效率随添加量增大而略有下降;羟基磷灰石使Pb、Cu、Zn和Cd的稳定态比例分别增加30.55%、16.83%、11.43%和15.39%,稳定态增加比例明显大于壳聚糖和单宁酸. 

Effects of Different Materials on the Stabilization of Heavy Metals in Sediments

Chitosan,tannic acid and hydroxyapatite were used to stabilize the heavy metals in contaminated sediment,and the stabilization efficiency was evaluated by the toxicity characteristic leaching procedure(TCLP) and form change of the heavy metals.The results showed that the three stabilizing agents significantly decreased the concentration of heavy metals in the leachates.With the addition of hydroxyapatite,the stabilization efficiencies of Pb,Cu,Zn and Cd were the highest,reaching 90.03%,80.46%,60.40% and 79.23%,respectively.The stabilization efficiency of heavy metals by tannic acid was less,and the stabilization efficiency of Zn decreased slightly with increased amount of chitosan.With the addition of hydroxyapatite,the stable speciation proportions of Pb,Cu,Zn and Cd increased by 30.55%,16.83%,11.43% and 15.39%,respectively,which was obviously greater than the effects of either tannic acid or chitosan.