RETRACTED: Operating Variables in Chemical Extraction of Heavy metals from Contaminated Soils (Retracted Article)

Heavy metals contamination in soils is widespread across the world, and the remediation of these soils is a difficult task. One possible technique for remediation of soils contaminated by heavy metals is soil washing using chelating agents. Ethylenediaminetetraacetic acid (EDTA) and Citric acid (CA) are very effective chelating agents for this purpose. The aim of this study is to investigate the optimum conditions for extraction of Cu, Pb, Ni, Zn and Cd considering tow factors-contact time and pH value and to evaluate the possibility of ultrasonic extraction as potential alternatives compared with oscillation for speedy. With the increase of molar ratio (chelating agents/heavy metal), the amounts of heavy metals extracted from these artificial contaminated soils increased. A ratio of 10 between chelating agents and the heavy metal is required for a higher extraction rate no matter the agent is EDTA or CA. Experiments showed for all heavy metals that acidity was benefit for extraction. A higher removal efficiency was easily achieved at a pH value of 3 similar to 4. Extractions of metals reached satisfactory efficiency in a relatively short time by ultrasonic compared with that by oscillation. In apply of soil washing for soils contaminated by heavy metals, the use of ultrasonic has a great potential to achieve rapid extraction purposes. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Organizers of 2011 International Conference on Energy and Environmental Science.