膨润土对底泥重金属的抑制效果及机制探讨

Suppressing Cu^(2+),Pb^(2+) and Zn^(2+) Ions Liberation from Suzhou Creck Sediment Used by Bentonite

采用底泥原地稳定化处理技术中的帽封方法,考察膨润土对苏州河底泥中Cu2+、Pb2+和Zn2+3种重金属离子释放的抑制效果。结果表明:钙基膨润土对Cu2+、Pb2+和Zn2+的最大吸附容量分别为273.4 mg.g-1、473.6mg.g-1和263 mg.g-1;均具有较强的吸附性能;且在溶液pH值升高时,其对Cu2+、Pb2+和Zn2+的吸附效果增强。在Zn-Pb混合体系下,钙基膨润土对Pb2+吸附效果增强,Zn2+的吸附效果不明显;而在Zn-Cu混合体系下,钙基膨润土对Cu2+效果增强,对Zn2+的吸附效果减弱。

The effect of suppression on Cu2＋,Pb2＋ and Zn2＋ heavy metal ions from Suzhou Creck sediment by using calcium bentonite as capping material for in-situ sediment treatment.The results showed that the maximum adsorption capacity of Cu2＋,Pb2＋ and Zn2＋ were 273.4 mg·g-1,473.6 mg·g-1 and 263 mg·g-1,respectively.And the adsorption efficiency of bentonite on these metal ions was increased with pH increasing.In Zn-Pb coexisting system,the adsorption efficiency of bentonite on Pb2＋ ion was increased obviously.However,the little effect on Zn2＋ was found.The adsorption efficiency of bentonite on Cu2＋ ion was enchanced in Zn-Cu coexisting system,but which was decreased on Zn2＋.