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| Heavy metal removal in reclaimed tidal flat soil from the Pearl River estuary by immersion in saline water |
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Abstract An experiment was conducted to remove heavy metals in reclaimed tidal flat soil from the Pearl River estuary by immersion in NaCl solution. The effects of immersion durations and NaCl concentrations on the removal of six heavy metals were examined. The chemical forms of heavy metals in soil before and after immersion were also determined. Removal rate of heavy metals was the maximum at 60d or NaCl 16g/L immersion, being 30.3% for Cd, 9.4% for Pb, 8.0% for Cu, 22.0% for Zn, 12.6% for Cr and 9.9% for Ni, and 41.9% for Cd, 9.3% for Pb, 6.3% for Cu, 19.9% for Zn, 14.8% for Cr and 16.8% for Ni, respectively. Speciation changes of heavy metals in the treated soil indicated that NaCl was effective in removing the exchangeable, carbonate and oxide forms of heavy metals, but ineffective for their organic and residual forms.
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Received: 20 July 2009
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