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Remediation of trace metal contaminated soils / Remediation if trace metal

The chelating agent ethylene diamine tetraacetic acid (EDTA) is promising. The ligand is more effective in removing the metal contaminants from soils than HCl. In a batch experiment, EDTA released a large portion of metals from soils to soil extracts. A batch method was also developed for recovering the metal contaminants in the resulting EDTA soil-extracts. Using an anion exchange resin (AER) AG 3-x4, up to 99% of the Cd, Cu, Pb, and Zn were removed from the leachates. / To increase the efficacy of the extraction method we tested different reagent, amount, and technical application strategies using soil columns. Mixing the reagent with the whole soil column was found to be the most efficient method for the application of the chelating agent for the purpose of metal extraction from soils. It was found that EDTA was superior to citric acid in removing Cd, Cu, Pb, and Zn from the soils investigated. Up to 27% more Cd, 23% more Cu, 42% more Pb, and 21% more Zn were removed by the EDTA and the removal was further increased with the addition of an acid/salt solution (1.0 M HCl and 1.0 M KCl) to the columns. Other promising results are that the AER in columns is an effective method for extracting metals from EDTA soil-extracts with different properties. The resin column method was found to be more efficient than the resin batch procedure. / The results of the simulated field experiment confirmed that the remediation of contaminated soils can be achieved using EDTA. The majority of the contaminated soils were decreased to the point that they could be reused for commercial and/or residential use. / Computer models can be used to predict the possible metal speciation and interaction with solid surfaces in soils. Using the MINEQL+ program, the models estimated that most of the metal species in the soil extracts (in the presence of EDTA, chloro, hydroxo, and carbonato ligands and humate and hydrous ferric oxide (HFO) solid phases) were present as soluble metal-EDTA complexes. It appears that the metal-EDTA complexes found in the systems are very stable over a wide range of soil pH. Our surface complexation models also indicated that the EDTA is much stronger than the humate and the HFO solid phases in forming complexes with the metals. As a consequence, the adsorption of the Cd, Cu, Pb, and Zn by the solid surfaces was negligible in the presence of EDTA. (Abstract shortened by UMI.)

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.36718
Date January 1999
CreatorsTejowulan, Raden Sri.
ContributorsHendershot, W. H. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageDoctor of Philosophy (Department of Natural Resource Sciences.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001763826, proquestno: NQ64679, Theses scanned by UMI/ProQuest.

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