【作者】 单红丹；

【导师】 卢升高；

【作者基本信息】 浙江大学 ， 土壤学， 2006， 硕士

【摘要】 随着现代工业的发展,人们越来越关注重金属污染对生态环境和人类健康的影响。本文利用富铁环境物质对土壤和水体中重金属的吸附与固定作用进行了下列研究:（1）、通过磁分离提取粉煤灰中的磁性物质,分析了反应时间、pH、吸附质浓度和离子强度对磁性物质吸附水体中重金属离子Cd²⁺、pb²⁺、Cu²⁺的影响。（2）、通过向土壤中添加富铁环境物质的培育试验,分析富铁环境物质对土壤中重金属的化学形态和TCLP与EDTA提取态重金属含量的影响。结果表明: 三种磁性物质样品对重金属的吸附极为迅速,其中以Pb²⁺最为迅速,Cd²⁺次之,Cu²⁺约在6小时达到平衡;电解质浓度变化对三种重金属离子吸附效果影响程度大小为Cu²⁺>Cd²⁺>pb²⁺,在0.2、0.6和1.0mol/L下pb²⁺的吸附量基本没有变化;pH值变化对三种重金属离子吸附效果影响程度大小为Cu²⁺>Cd²⁺、Pb²⁺,表现为随着pH升高,吸附量显著降低。磁性物质对Cd²⁺、Cu²⁺的吸附符合Langmuir吸附等温线。 土壤中添加三种富铁环境物质（粉煤灰、铁尾矿和钢渣中提取的磁性物质）后,重金属化学形态的分析结果表明,重金属（Cd、Cu、Pb、Zn）的形态以铁锰结合态所占比重最大,可交换态所占比重最小,表明富铁环境物质对重金属起到了一定的固定作用。应用TCLP法对重金属（Cd、Cu、Pb、Zn）的环境毒性分析表明,土壤中添加富铁环境物质后TCLP法提取的重金属含量降低,EDTA法提取的生物有效性重金属含量也有不同程度降低。表明富铁环境物质对土壤中重金属起到一定的固定作用。更多还原

【Abstract】 With the development of modern industry, more and more attention has been given to the influence of heavy metal pollution on eco-environment and human health. This paper deals with the adsorption and immobilization of heavy metals in soils and water by iron-rich environmental materials, such as flay ash, iron oxide tailing and bust furnace slag. The effects of contact time, pH, the initial concentration and ionic strength on the adsorption of heavy metal ions Cd²⁺, Pb²⁺, Cu²⁺ on magnetic materials separated from fly ashes were evaluated by using batch adsorption experiments. Based on the laboratory culture experiments of added iron-rich environmental materials to soils, the heavy metal chemical fractions and extraction concentrations by TCLP and EDTA procedures are analyzed. Results were as followings:The batch experiments showed that magnetic materials adsorbed rapidly heavy metals and reached equilibrium within 6 hours. The adsorption rate followed the order of Pb²⁺>Cd²⁺>Cu²⁺. The electrolyte intensity affected strongly adsorption capacity of Cu²⁺ and Cd²⁺ on magnetic materials. However, adsorption of Pb²⁺ on magnetic materials showed little differences in the range of 0.2 to 1.0 mol/L levels of electrolyte. The heavy metals adsorption on the magnetic materials tended to decrease with an increase of pH. The curves of isothermal adsorption of Cd²⁺, and Cu²⁺ on magnetic materials were well fitted by the Langmuir equation.The immobilization efficacy of iron-rich environmental materials （magnetic materials extracted from fly ash, iron mine tailing and steel slag） was evaluated by applying 5-stage sequential extraction, US EPA TCLP test and EDTA leaching test on the mixtures of iron-rich materials with two kinds of soils. The 5-stage sequential extraction results indicated that the application of iron-rich environmental materials resulted in changes of chemical fractions of heavy metals. The heavy metals were dominantly associated with Fe/Mn oxide fraction and least exchangeable fraction. The TCLP solubilities of Cd, Cu, Pb, Zn were reduced due to the addition of iron-rich environmental materials to soils. The EDTA leaching test indicated that the bioactive concentrations of heavy metals were also decreased. The results showed iron-rich environmental materials had a potential capacity of adsorption of heavy metals in thecontaminated soils.更多还原