Chelating Extraction of Zinc from Soil Using <i>N</i>-(2-Acetamido)iminodiacetic Acid

Hong, Andrew; Chen, T. C.; Okey, Robert W.; Tedder, D. W.; Pohland, F. G.

doi:10.1021/bk-1995-0607.ch017

Cited by 6 publications

(2 citation statements)

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“…To minimize the environmental disturbance, various chelating agents have been tested in lieu of acids. Chelating agents studied thus far include pyridine-2,6-dicarboxylic acid (PDA) (11), N-(2-acetamido)iminodiacetic acid (ADA) (12), nitrilotriacetic acid (NTA) (13), and ethylenediaminetetraacetic acid (EDTA) (3,6,7,13,14), of which EDTA has received the most attention for its ability to form strong complexes with transition metals. However, EDTA flushing generates large volumes of metal-and EDTA-laden wastewater, which requires costly additional treatment or disposal.…”

Section: Introductionmentioning

confidence: 99%

Removal of Copper from Contaminated Soil by Use of Poly(amidoamine) Dendrimers

Zhao

2005

Environ. Sci. Technol.

141

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This study characterizes poly(amidoamine) (PAMAM) dendrimers of various generations and terminal functional groups for removal of copper(II) in a sandy soil. Effects of dendrimer dose, generation number, pH, terminal functional groups, and ionic strength on the removal efficiency were investigated through a series of column tests. Over 90% of copper initially sorbed in the soil was removed by use of approximately 66 bed volumes of 0.10% (w/w) of a generation 4.5 dendrimer with carboxylate terminal groups at pH 6.0. On the basis of equal equivalent dose, dendrimers of lower generation removed more copper. Lowering pH enhanced copper removal for all dendrimers tested. In contrast, types of terminal groups (carboxylate, amine, or hydroxyl) showed a modest effect on the removal efficiency. Results from a sequential extraction procedure suggested that dendrimers removed primarily exchangeable and carbonate-bound copper. The residual copper in treated soil is predominantly bound with soil organic matter (SOM), which is much less available physical-chemically or biologically. Spent dendrimers were recovered through nanofiltration with a commercially available nanofilter. Upon acid regeneration, recovered dendrimers were reused and performed as well as the virgin dendrimers. The dendrimers may be used as reusable, high-capacity extracting agents for in situ removal of heavy metals from contaminated soils.

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Section: Introductionmentioning

confidence: 99%

Removal of Copper from Contaminated Soil by Use of Poly(amidoamine) Dendrimers

Zhao

2005

Environ. Sci. Technol.

141

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“…Chelating extraction of heavy metals with an emphasis on recovering and reusing the chelating agents has only been addressed recently. [15][16][17][18][19][20][21] These recent studies have demonstrated the recovery of metals following chelating extraction via (1) the use of electrochemicalmethod to recover strong chelator EDTA, and (2) the elevation of solution pH to recover those chelators of moderate strength.…”

Section: Introductionmentioning

confidence: 99%

Chelating Agents for Extraction of Heavy Metals from Soil

Hong

Jiang

et al.

Emerging Technologies in Hazardous Waste Management 8

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Chelating extraction of heavy metals from contaminated soils is seen as a remediation technique. This work addresses important consideration in the application of chelating agents for soil remediation, namely the complexing power, selectivity, and recoverability of the chelators with respect to heavy metal contaminants. To address these issues, an assessment technique was developed to evaluate the chelators based on complexation equilibria of the chelators toward the target metals including Pb, Cu, Cd, Zn, Ni, and Hg. Predictions in terms of complexing power and selectivity were made using this technique and were compared to experimental extraction results using several chelators including L-5-glutamyl-L-cysteinylglycine (GCG), ethylenediaminetetraacetic acid (EDTA), nitrilotris(methylene)triphosphonic acid (NTTA), and trimethylenedinitrilotetraacetic acid (TMDTA). Experimental results showed an increasing complexing ability in the order of GCG < NTTA < TMDTA < EDTA, and an increasing selectivity toward the metal contaminants in the order of EDTA < TMDTA < GCG < NTTA. These results were largely consistent with equilibrium predictions. Enhanced recovery of metals from a very strong chelator EDTA was demonstrated with the use of metal-competing cationic precipitants (calcium hydroxide and ferric chloride) or anionic sulfide precipitant.

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