Journal of Engineering (Jan 2015)
Extraction of heavy metals from contaminated soils using EDTA and HCl
Abstract
The present study examines the extraction of lead (Pb), cadmium (Cd) and nickel (Ni) from a contaminated soil by washing process. Ethylenediaminetetraacetic acid disodium salt (Na2EDTA) and hydrochloric acid (HCl) solution were used as extractants. Soil washing is one of the most suitable in-situ/ ex-situ remediation method in removing heavy metals. Soil was artificially contaminated with 500 mg/kg (Pb , Cd and Ni ). A set of batch experiments were carried out at different conditions of extractant concentration , contact time, pH and agitation speed. The results showed that the maximum removal efficiencies of (Cd, Pb and Ni ) were (97, 88 and 24 ) % respectively using ( 0.1 M) Na2EDTA. While the maximum removal efficiencies using (1M) HCl were (98, 94 and 55)% respectively. The experimental data of batch extraction were applied in four kinetic models; first order, parabolic diffusion, two constant and Elovich model. The parabolic diffusion was the most fitted to the experimental data.