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Removal of Cd and Pb in Calcareous Soils by Using Na2EDTA Recycling Washing
Soil‐column experiments were conducted for removing of Cd and Pb from calcareous soils by using EDTA disodium (Na2EDTA). Up to 84.4 and 73.5% of diethylenetriaminepentaacetic acid (DTPA)‐extractable Cd and Pb were removed by using 0.04 mol L−1 Na2EDTA at 1:8 of soil‐to‐solution ratio (w/v). More than 99% of Cd and 97% of Pb in leachate collected from washing procedure were precipitated at pH 10 by using Na2S + Ca(OH)2, while only 56.9% of Cd and 97.5% of Pb were removed with FeCl3 + NaOH. The recovered Na2EDTA from leachate treatment did not lose much of its chelating capacity in the first washing process. However, in the second and third batch washing process, the removal of DTPA‐extractable Cd decreased by 26.2 and 20.2%, while the removal of DTPA‐extractable Pb decreased by 33.0 and 41.1%, respectively. Due to the high content of Na+ in the treated soil, several chemical amendments were employed to remove Na+. (NH4)2SO4 was the most suitable amendment reagent and the optimal concentration of (NH4)2SO4 was 0.08 mol L−1 at a soil‐to‐solution ratio of 1:3. The total cost for recycled Na2EDTA washing decreased by 68.9% as compared with fresh Na2EDTA washing.
Removal of Cd and Pb in Calcareous Soils by Using Na2EDTA Recycling Washing
Soil‐column experiments were conducted for removing of Cd and Pb from calcareous soils by using EDTA disodium (Na2EDTA). Up to 84.4 and 73.5% of diethylenetriaminepentaacetic acid (DTPA)‐extractable Cd and Pb were removed by using 0.04 mol L−1 Na2EDTA at 1:8 of soil‐to‐solution ratio (w/v). More than 99% of Cd and 97% of Pb in leachate collected from washing procedure were precipitated at pH 10 by using Na2S + Ca(OH)2, while only 56.9% of Cd and 97.5% of Pb were removed with FeCl3 + NaOH. The recovered Na2EDTA from leachate treatment did not lose much of its chelating capacity in the first washing process. However, in the second and third batch washing process, the removal of DTPA‐extractable Cd decreased by 26.2 and 20.2%, while the removal of DTPA‐extractable Pb decreased by 33.0 and 41.1%, respectively. Due to the high content of Na+ in the treated soil, several chemical amendments were employed to remove Na+. (NH4)2SO4 was the most suitable amendment reagent and the optimal concentration of (NH4)2SO4 was 0.08 mol L−1 at a soil‐to‐solution ratio of 1:3. The total cost for recycled Na2EDTA washing decreased by 68.9% as compared with fresh Na2EDTA washing.
Removal of Cd and Pb in Calcareous Soils by Using Na2EDTA Recycling Washing
Zhang, Shujuan (author) / Yang, Zhihui (author) / Wu, Baolin (author) / Wang, Yangyang (author) / Wu, Ruiping (author) / Liao, Yingping (author)
CLEAN – Soil, Air, Water ; 42 ; 641-647
2014-05-01
7 pages
Article (Journal)
Electronic Resource
English
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