污泥中重金属形态分布与可浸出性的相关性研究

Correlation between chemical forms and leachability of heavy metals in sludge samples

选取4个典型的城市污水厂的污泥为试验样品,研究了污泥中Cu,Zn,Ni,Cr,Pb和Mo的化学形态分布以及可浸出性,并对金属的形态分布与浸出量进行相关性分析.结果表明:Zn主要以可交换态和可还原态形式存在于污泥中,Cu和Pb主要以可氧化态形式存在,Ni,Cr,Mo主要以残渣态赋存.在相同浸出条件下,金属的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,其中金属的浸出量与其在污泥中的可交换态和可还原态含量之间具有明显的正相关性.

Sludge samples were collected from four typical municipal wastewater treatment plants. The sequential extraction procedure and leaching tests of heavy metals in sludge samples were performed to investigate the chemical forms of Cu, Zn, Ni, Cr, Pb, and Mo, and their correlation with the leachability. The results showed that Zn existed in sludge mainly in exchangeable form and reducible form, Cu and Pb mainly in oxidizable form, and Ni, Cr, and Mo mainly in residual form. Under the same condition of leaching tests, the leaching ratios of the metals were influenced significantly not only by the characteristics of the metals and sludge, but also by the chemical forms of the metals in sludge. Furthermore, the leaching amounts of the metals were of significant positive correlation with their exchangeable and reducible fractions.