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Impact of Chemical Leaching on Permeability and Cadmium Removal from Fine-grained Soils

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Publisher Springer
Date 2017 Jun 22
PMID 28634800
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Abstract

The aim of this study was to investigate the influence of chemical leaching on permeability and Cd removal from fine-grained polluted soils. Column leaching experiments were conducted using two types of soils (i.e., artificially Cd-polluted loam and historically polluted silty loam). Chemical agents of CaCl, FeCl, citric acid, EDTA, rhamnolipid, and deionized water were used to leach Cd from the soils. Results showed that organic agents reduced permeability of both soils, and FeCl reduced permeability of loam soil, compared with inorganic agents and deionized water. Entrapment and deposition of colloids generated from the organic agents and FeCl treatments reduced the soil permeability. The peak Cd effluence from the artificially polluted loam columns was retarded. For the artificially polluted soils treated with EDTA and the historically polluted soils with FeCl, Cd precipitates were observed at the bottom after chemical leaching. When Cd was associated with large colloid particles, the reduction of soil permeability caused Cd accumulation in deeper soil. In addition, the slow process of disintegration of soil clay during chemical leaching might result in the retardation of peak Cd effluence. These results suggest the need for caution when using chemical-leaching agents for Cd removal in fine-grained soils.

References
1.
Torkzaban S, Bradford S, Vanderzalm J, Patterson B, Harris B, Prommer H . Colloid release and clogging in porous media: Effects of solution ionic strength and flow velocity. J Contam Hydrol. 2015; 181:161-71. DOI: 10.1016/j.jconhyd.2015.06.005. View

2.
Kim J, Hyun S . Nonequilibrium leaching behavior of metallic elements (Cu, Zn, As, Cd, and Pb) from soils collected from long-term abandoned mine sites. Chemosphere. 2015; 134:150-8. DOI: 10.1016/j.chemosphere.2015.04.018. View

3.
Zhang W, Huang H, Tan F, Wang H, Qiu R . Influence of EDTA washing on the species and mobility of heavy metals residual in soils. J Hazard Mater. 2009; 173(1-3):369-76. DOI: 10.1016/j.jhazmat.2009.08.087. View

4.
Liao X, Li Y, Yan X . Removal of heavy metals and arsenic from a co-contaminated soil by sieving combined with washing process. J Environ Sci (China). 2016; 41:202-210. DOI: 10.1016/j.jes.2015.06.017. View

5.
Makino T, Sugahara K, Sakurai Y, Takano H, Kamiya T, Sasaki K . Remediation of cadmium contamination in paddy soils by washing with chemicals: selection of washing chemicals. Environ Pollut. 2006; 144(1):2-10. DOI: 10.1016/j.envpol.2006.01.017. View