Study On Leaching To Remidiation Of Heavy Metal-contaminated Soil Acid

Soil is the human survival natural resources.A large number of heavy metal through various channels brake into the environment with speeding up of the industry's rapid development and urbanization process.Soil with the heavy metal pollution,as environmental pollutants and the final carrier,pose more and more serious threat on humin been.Remediation of heavy metal contaminated soil has been a hot topic of research in the field of environmental science.The soil sample for this experiment was collected from farmlands nearby a zinc plant in Huludao City,Liaoning Province.The total Pb content was 210.6 mg/kg in soil,mainly at reduction state,accounted at 75.78%,secondly is the residual,accounted at 19.04%.The acid extractable and oxidized forms accounted for 3.68%and 2.50%at the respective,In this study,the contaminated soil was washed to remove Pb with colution containing citric acid,citric acid and sodium dodecyl benzene sulfonate respectively.Batch experiment was carried out to study the desorbing dynamic characteristics of Pb from the soil.The effect of different solidliquid ratio,leaching agent concentration,pH and temperature conditions on the washing was investigated.The results showd that two kinds of leaching agent composite leaching effect is relatively weak,which reflects the antagonism exists between them,and single citric acid leaching effect is well.When citric acid was used to leach Pb from the soil,the equilibrium was reached at 240 min,the first-order kinetic equation,quasi second order kinetic equation and double Changshu model are both suitable to descraption for the process of the leaching desorption kinetics.