Abstract
Batch extraction experiments were conducted to investigate the chemical washing of metal-contaminated paddy soils using mixtures of ferric chloride (FeCl3) and citric acid (CTA). The effects of the extractants (FeCl3, CTA, or FeCl3 + CTA) and washing cycles (single-step or multistep washing) on the metal removal efficiency were studied. FeCl3 + CTA increased metal removal efficiency to some extent compared to single FeCl3 or CTA. When the liquid-to-solid ratio was 2:1 with three washes and two rinses, a mixture of 10 mmol L−1 FeCl3 and 20 mmol L−1 CTA removed 78.9% Cd, 15.8% Cu, 34.0% Zn, and 18.1% Pb from a Typic Fe–accumuli–Stagnic Anthrosols. Using multistep washing instead of single-step increased the metal extraction effect. Moreover, the removal efficiency and speciation of metals in different soils and changes in soil properties in washed soils were also studied. The removal rate of Cd was higher than that of Zn, Cu, or Pb because of the higher proportions of acid-soluble forms of Cd in the soils. The removal of metals from different soils depended on the distribution of metal speciation and soil type. Soil pH, CEC, exchangeable Ca, and exchangeable Mg decreased significantly after soil washing. We conclude that chemical washing of metal-contaminated paddy soils with mixtures of FeCl3 and citric acid may be a feasible technique for soil remediation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
