Environmental Prediction Model for Dynamic Release of Lead in Contaminated Soil under Washing Remediation

 

Jiang-shan Li

State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; e-mail: whrsmljsh@163.com

Ping Wang

State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; e-mail: wp_cersm@163.com

Lei Liu

State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; e-mail: lliu@whrsm.ac.cn

 

 ABSTRACT

Adsorption-desorption characteristics and model for lead contaminated soil with different concentration were studied by batch tests in laboratory. Results showed that Langmuir equation could better fit isothermal adsorption curve of lead, with the increasing of lead in soil, the time for lead to reach equilibrium extended. Desorption process of lead under the washing of Na2EDTA could be divided into two phase, that was rapid desorption phase and slow desorption stage, and the turning point was about 200min. Dual constant equation could effectively reflect the desorption kinetics process of lead in contaminated soil. A dynamic model for describing the migration process of lead in contaminated soil under washing was established based on desorption kinetics equation, soil moisture migration equation and solute transport equation. Numerical solution for the model was solved and the validity of which was verified based on monitoring dates. The migration law of lead in contaminated soil under washing was obtained through numerical simulating of a simple condition.

Keywords: Lead contaminated soil; washing remediation; adsorption-desorption; prediction model.

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