铅在土壤中的吸附特性及形态分布研究

Study on adsorption characteristics and speciation distribution of lead in soil

采用动力学吸附模型和等温吸附模型,并结合BCR形态法和红外光谱方法,探究土壤对铅的吸附效果以及在土壤中的形态分布。结果表明,土壤中有机物质活性位点发生偏移,有机质组分能够吸持部分铅,但所吸附铅含量较少;铅在土壤中的吸附符合准二级动力学(R2=0.9976)和Freundlich等温模型(R2=0.9882),铅的最大吸附量为72.68 mg/g,主要以化学吸附为主;土壤中的铁锰氧化物对铅的吸附量最高能达到85.27%,因此,土壤中的铁锰氧化物可以作为良好的稳定化药剂运用于修复铅污染土壤。

Using the adsorption capacity of each component to lead(Pb)in the soil in the kinetic adsorption model and isothermal adsorption model combined with the BCR form method and infrared spectroscopy characterization method to investigate the adsorption effect of soil on lead and its distribution in soil.The results show that the active site of organic matter in the soil is shifted,and the organic matter fraction can absorb part of the lead,but the adsorbed lead content is less.Adsorption kinetics experiments showed the best fit using quasi-secondary kinetics(R=0.9976),using the Freundlich model(R=0.9882),and the maximum adsorption of lead was 72.68 mg/g,indicating that the adsorption of lead in soil is mainly chemisorption.The iron and manganese oxides in the soil can adsorb up to 85.27%of lead.The above results can thus indicate that the iron and manganese oxides can be used as a good stabilizing agent in repairing Pb contaminated soil.