Extraction of Heavy Metals by Mercaptans Attached to Silica Gel by a Corkscrew Mechanism

Bowe, Craig A.; Benson, Robert F.; Martin, Dean F.

doi:10.1081/ese-120013264

Cited by 6 publications

(2 citation statements)

References 6 publications

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“…Examples of such ligands include LIX54 [CH 3 (CH 2 ) 11 C 6 H 4 COCH 2 COCH 3 ], LIX860 (n-dodecylsaldoximine), oleoylacetone, and N, N'-didodecyldithiooxamide (all were once commercially available). A two-step procedure was used [24][25][26][27]: First, silica gel (5 g) was mixed with 25 mL of hexane, and the excess solvent allowed to evaporate to produce silica gel with pores loaded with hexane. Next the treated silica gel was mixed with a solution of a chelating agent in hot hexane.…”

Section: London-forces (Corkscrew) Approachmentioning

confidence: 99%

“…The second result, as a consequence, was the ability to reduce the fresh water intake by recycling reducing water usage by 67%. A second example involved a similar unit installed at a gold mine located in mountains west of Denver, Colorado [27].The chief contaminant in the mine drainage water was zinc, and about 4 million gallons of mine drainage waster was discharged yearly at the gold mine. A two-fold treatment was tested.…”

Section: Company Literaturementioning

confidence: 99%

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Chromatographic Separations with Selected Supported Chelating Agents

Martin¹

2013

Column Chromatography

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Chelex is another example of a commercially available supported chelating agent. The material was available from "io-Rad and was used to purify compounds, most notably transition metal ions. [ ] The preference for transition metal ions, e.g., copper II or iron II ions, over such univalent metal ions as sodium or potassium is said to be about to [ ]. The material consists of a styrene-divinylbenzene copolymer to which is attached iminodiacetic acid moieties.In addition, Chelex can be used for purification of DN" [ ]. Though the mechanism of action seems uncertain, a plausible suggestion is that Chelex protects DN" from the effect of heating that is used to release DN" from cells. In addition, Chelex can sequester magnesium and heavy metal ions that would adversely affect the DN". "fter treatment, DN" and RN" remain in the aqueous supernatant above the Chelex sample.Supported chelating agents serve three major functions, i.e., concentration, elimination, and recycling metal ions. Concentration of metal ions is a significant function that enhances analytical capabilities.Measuring the concentration of trace metals in dilute sea water is a significant analytical challenge. Using supported chelators allows an analyst to concentrate transition metals present in trace amounts from a large volume of sea water onto a solid in, say, a chromatography column, then eluting with dilute nitric acid to obtain a suitably concentrated solution. The technique can also be used to eliminate matrix effects. Unfortunately, Chelex seems to be less effective in sea water than in fresh water [ ]."lso, users of Chelex may encounter problems with certain natural waters that are colored with samples of naturally occurring chelating agents such as soil organic acids e.g., fulvic or humic acids that provide competition for metal ions and reduce the effectiveness of Chelex [ , ]. Ryan and Weber [ ] studied this problem and made pre-concentration comparisons of trace levels of copper ion in standard solutions comparing Chelexwith three different chelating agents supported on silica. The reagents tested were N-propylethylenediamine, the bis-dithiobicarbonate of that compound, and -hydroxyquinoline. The results indicated that in the presence of organic compounds typical organic-rich natural waters reduced the effectiveness of Chelexin comparison with the three silica-supported agents. In general, immobilizedquinolinol was the most effective, as prepared by a modified Hill procedure [ ].It is not the purpose of this review to criticize use of a successful commercial supported chelator rather one may note that no such product can be expected to be highly effective under all conditions and circumstances, so it seems appropriate to consider examples of custom-made agents.

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Section: London-forces (Corkscrew) Approachmentioning

confidence: 99%

Section: Company Literaturementioning

confidence: 99%

Chromatographic Separations with Selected Supported Chelating Agents

Martin¹

2013

Column Chromatography

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Liquid–liquid microextraction based on a dispersion of Pd nanoparticles combined with ETAAS for sensitive Hg determination in water samples

Martinis

Escudero

Salvarezza

et al. 2013

Talanta

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Comparison of anion removal capacities of Octolig® and Cuprilig

Martin

Franz

2011

Journal of Environmental Science and Health, Part A

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Mixtures of sodium salts of phosphate, arsenate, and fluoride were used in chromatography and batch experiments to compare the capacity of two immobilized ligands (IMLIGs) to remove these anions: Octolig and its copper (II)-based metallolig, Cuprilig. The focus of this study was twofold. First, to find out which material, Octolig or Cuprilig, would remove these anions most effectively; and secondly to determine the optimal capacity for removal of representative anions. Removal capacity was evaluated by two methods: by chromatography and by a batch method. The methods gave identical results, but the batch method was more convenient. Cuprilig had a lower capacity for removal of phosphate than Octolig. The capability of Octolig for removing anions was: phosphate > arsenate > fluoride >>> chloride >>>> bromide. Replication of phosphate removal was good for a given batch of Octolig. Of three different samples of Octolig, two seemed to be alike based on the phosphate- removal capacity; the third was different on the basis of a Student's t-test. This distinction indicates the batch procedure could serve as a quality control/assurance technique.

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Extraction of Heavy Metals by Mercaptans Attached to Silica Gel by a Corkscrew Mechanism

Cited by 6 publications

References 6 publications

Chromatographic Separations with Selected Supported Chelating Agents

Chromatographic Separations with Selected Supported Chelating Agents

Liquid–liquid microextraction based on a dispersion of Pd nanoparticles combined with ETAAS for sensitive Hg determination in water samples

Comparison of anion removal capacities of Octolig® and Cuprilig

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