Application of EDTA decontamination on soils affected by mining activities and impact of treatment on the geochemical partition of metal contaminants

Xia, Wei; Gao, Hui; Wang, Xianhai; Zhou, Chunhua; Liu, Yunguo; Fan, Ting; Wang, Xin

doi:10.1016/j.jhazmat.2008.08.092

Cited by 31 publications

(13 citation statements)

References 29 publications

(28 reference statements)

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“…The advantages of using chelating agents in sediment washing are higher efficiency of metal extraction, higher thermodynamic stabilities of the metal complexes formed, higher solubilities of metal complexes, and lower adsorption of the chelating agents and their metal complexes on sediments (Fischer et al 1998;Zhang and Lo 2006). In comparison with other chelating agents, EDTA has a high level of complex capacity with respect to heavy metals (Abumaizar and Smith 1999;Martinez 2000;Xia et al 2009). Although EDTA is effective on removing heavy metals from contaminated soils, the treatment agents must come into contact with the target contaminants.…”

Section: Introductionmentioning

confidence: 99%

“…Although EDTA is effective on removing heavy metals from contaminated soils, the treatment agents must come into contact with the target contaminants. However, access to the target contaminants is often hampered by the soil matrix that physically shields the contaminants from exposure to the treatment agent in solution, resulting in poor or incomplete removal of the target contaminants (Cassidy and Irvine 1998;Xia et al 2009). Mechanical agitation has been applied to allow effective contact of contaminants with the chemical agents.…”

Section: Introductionmentioning

confidence: 99%

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Pressure-assisted cyclic washing of heavy-metal-contaminated sediments

Lin

Peng

Chiu

et al. 2013

Int. J. Environ. Sci. Technol.

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Remediation of heavy-metal-contaminated sediment is often hampered by the availability of heavy metals to the added chemical agents because the heavy metals are often shielded by the sediment matrix. Effective heavy-metal extraction technique becomes an important factor in enhancing the treatment efficiency. A novel extraction/washing technique utilizing chelating agent and elevated pressure in consecutive cycles of compression and decompression has been developed for heavy-metal-contaminated sediment washing in the presence of chelating agent. In this study, the optimal operational conditions of pressure-assisted cyclic washing of Cu-contaminated sediments (initial Cu concentration = 23.177 mg/kg) were determined in a laboratory-scale system. The control factors included applied pressure level, washing time, applied chelant [ethylenediamine-tertraacetic (EDTA)] concentration (0.01-0.5 M), pressure times, and application of consecutive batches washing. Results from the bench-scale study showed that up to 70 % of Cu can be removed from the sediments when 10 atm of pressure was applied for washing. The efficiency dropped to 55 % when the pressure dropped to 6 atm. Under the same operational conditions, the optimal cyclic washing time was 60 min.Results from the particle size analyses indicate that the mean particle size dropped from 100 to 50 lm after the pressure-assisted cyclic washing. Thus, cyclic pressure caused the fracture of sediment aggregates resulting in the exposure of Cu to chelating agents. With the assistance of pressure cyclic system, the total washing time and the amount of added chemical agent used can be significantly reduced.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pressure-assisted cyclic washing of heavy-metal-contaminated sediments

Lin

Peng

Chiu

et al. 2013

Int. J. Environ. Sci. Technol.

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show abstract

“…Ethylene diamine tetra-acetic acid and its salts (EDTA) have been extensively reported to appreciably increase the dissolution and mobility of heavy metals [7,[22][23][24][25], having themselves a low aquatic toxicity and no bioaccumulation in organisms throughout the food chain [26]. Therefore, EDTA was selected as the representative chelator Nomenclature M i metal concentrations in the solid/solution extraction with HNO 3 /H 2 SO 4 solution (pH 3.2) [mg l −1 ] MI i M i /R i , metal mobility index, dimensionless number N total the overall normality of S1 and S2 fractions in Cu, Cr, Ni, Pb, and Zn in the original soil [equiv.…”

Section: Introductionmentioning

confidence: 99%

Influence of soil washing with a chelator on subsequent chemical immobilization of heavy metals in a contaminated soil

Zhang

Tong

Yuan

et al. 2010

Journal of Hazardous Materials

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“…Fluid injection can be followed by downgradient extraction of groundwater mixed with the flushing solution, aboveground treatment and discharge, or reinjection of the fluid (GWRTAC, 1998). Research in this field remains limited, although chemically-enhanced flushing could be used to remove a wide variety of metals (Mulligan et al, 2001a,b;Jean et al, 2007;Tsang et al, 2007;Lestan et al, 2008;Xia et al, 2009). However, flushing is less efficient in porous media with low hydraulic conductivity (b10 −7 m/s).…”

Section: Introductionmentioning

confidence: 99%