Effect of Na+ on Removal Behaviors of Heavy Metals from Contaminated Silty Soils Flushed by EDTA
A series of Pb and Cu contaminated silty soil columns were made to simulate contaminated site, and ethylenediaminetetraacetic acid disodium saltdihydrate (EDTA) was used to flush contaminated soils. The concentration of Na+ and heavy metal concentrations were considered to study the removal behaviors of heavy metals. Studies show that the existence of Na+ inhibits the removal efficiency of both Cu and Pb from contaminated silty soils. The inhibitory effect of Na+ on Cu removal efficiency becomes smaller when increasing the concentration of Cu, and removal ratio of Cu is decreased by 25.8–39.0% when the concentration of Na+ is 100 mg/kg. The inhibitory effect of Na+ on Pb removal efficiency becomes stronger when increasing the concentration of Pb, and removal ratio of Pb is decreased by 10.1–29.4% when the concentration of Na+ is 200 mg/kg. The removal difference caused by different concentration of Na+ is not that obvious as increasing the concentration of heavy metals in contaminated soils. The results can provide some theoretical basis for in situ soil flushing to remediate heavy metal contaminated soil.
KeywordsRemoval Heavy metal Contaminated silty soil Flushing
The authors would like to express their sincere gratitude to the National Science Foundation of China (grant 51678311 and 51308310) and Key Project for Social Development of Ningbo City (Grant 2017C510002) for their financial support of this study. Also, this study is sponsored by K. C. Wong Magna Fund in Ningbo University.
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