污泥中重金属的形态分析及其可浸出性

Morphological Analysis and Leachability of Heavy Metals in Sludge

以自来水厂和污水处理厂的污泥为研究对象,采用Tessier五步法和火焰原子吸收光谱法研究污泥中重金属(Zn、Cu、Cd、Ni、Mn)含量、形态分布以及可浸出性。结果发现,在自来水厂污泥和污水处理厂污泥中重金属总量大小依次为Zn>Mn>Ni>Cu>Cd,Zn>Mn>Cu>Ni>Cd,污泥中Zn含量最高,为448.17mg.kg-1;Cd含量最低,为27.17mg.kg-1,超过国家标准,限制了污泥的农用。Tessier形态分析结果表明,污泥中Zn、Cu、Cd主要以稳定态存在;Mn主要以有效态存在,潜在的迁移性和植物毒性最值得关注;Cu浸出率最高,为14.8%,Zn浸出率最低,为0.11%,因此浸出率不仅与金属和污泥的特性有关,而且金属在污泥中赋存的化学形态对其可浸出性也有重要的影响。

Total amounts and morphological analysis of heavy metals including Cu,Zn,Cd,Ni,Mn in the sludge from waterworks and wastewater treatment plant were determined by five steps sequential extraction Tessier method and atomic absorption spectrometer method,and the leachability was also studied.Results showed that the total amounts of heavy metals in sludge from waterworks in the order from high to low were ZnMnNiCuCd,and the total amount of heavy metals in sludge from wastewater treatment plant were ZnMnCuNiCd.The Zn total amount of 448.17mg·kg-1 was higher than those.The Cd total amount of 27.17mg·kg-1 was lower than those.However,content of Cd was beyond the state control national standard of sludge for agricultural application,and that limited their agricultural application.Results of the Tessier morphological analysis indicated Zn,Cu,Cd were distributed mainly in the stable state,and Ni、Mn mainly in available state,and its mobility and phytotoxicity were worth of attention.The Cu leachability rate of 14.8% was highest,and the Zn leachability rate of 0.11% was lowest.leachability rate was influenced significantly not only by the characteristics of the metals and sludge,but also by the chemical form of heavy metals in sludge.