Removal of Cd and Pb in Calcareous Soils by Using Na2EDTA Recycling Washing. Issue 5 (4th October 2013)

• Record Type: Journal Article
• Authors: Zhang, Shujuan; Yang, Zhihui; Wu, Baolin; Wang, Yangyang; Wu, Ruiping; Liao, Yingping
• Is Part Of: Clean. Volume 42:Issue 5(2014:May)
• Page Start: 641
• Page End: 647
• Publication Date: 2013-10-04
• Subjects: Water quality -- Periodicals; Water -- Pollution -- Periodicals; Pollution -- Periodicals; Bioremediation -- Periodicals; Sewage -- Periodicals; Water chemistry -- Periodicals; 333.7205
• DOI: 10.1002/clen.201200634
• Languages: English
• ISSNs: 1863-0650

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="clen201200634-sec-0001" sec-type="section"> <p>Soil‐column experiments were conducted for removing of Cd and Pb from calcareous soils by using EDTA disodium (Na<sub>2</sub>EDTA). Up to 84.4 and 73.5% of diethylenetriaminepentaacetic acid (DTPA)‐extractable Cd and Pb were removed by using 0.04 mol L<sup>−1</sup> Na<sub>2</sub>EDTA 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 Na<sub>2</sub>S + Ca(OH)<sub>2</sub>, while only 56.9% of Cd and 97.5% of Pb were removed with FeCl<sub>3</sub> + NaOH. The recovered Na<sub>2</sub>EDTA 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<sup>+</sup> in the treated soil, several chemical amendments were employed to remove Na<sup>+</sup>. (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> was the most suitable amendment reagent and the optimal concentration of (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> was 0.08 mol L<sup>−1</sup> at a soil‐to‐solution ratio of 1:3. The total cost for recycled Na<sub>2</sub>EDTA washing decreased by 68.9% as compared with fresh Na<sub>2</sub>EDTA washing.</p> </sec> </abstract>