Removal of heavy metal ions from aqueous solutions using dithiooxamides supported on silica gel

Pooré, Duke D.; Benson, Robert F.; Martin, Dean F.

doi:10.1080/10934529609376484

Cited by 7 publications

(3 citation statements)

References 5 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%

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%

Chromatographic Separations with Selected Supported Chelating Agents

Martin¹

2013

Column Chromatography

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“…Also, selective separation of some metals from other components is of practical interest, either with the aim to isolate such elements from natural sources or for the purpose of their separation from industrial effluents or wastewater with respect to the low concentration. [1][2][3][4][5] Poly(vinyl alcohol) PVA is a well-known membrane material with good film-forming properties, is a highly hydrophilic polymer, and has easy availability. Investigations have been done on its use in the field of separation processes.…”

Section: Introductionmentioning

confidence: 99%

Preparation of poly(vinyl alcohol) grafted with acrylic acid/styrene binary monomers for selective permeation of heavy metals

El‐Rehim

Hegazy

Ali

1999

J. Appl. Polym. Sci.

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ABSTRACT:A study was made to modify water-soluble poly(vinyl alcohol) (PVA) by grafting acrylic acid and styrene (AAc/Sty) comonomers using gamma rays as an initiator. The factors that affect the preparation process and grafting yield were studied and more economical grafts under the most favorable reaction conditions were obtained. It was found that the high degree of grafting in such systems was obtained in the presence of an ethanol-water mixture in which water plays a significant role in enhancing the graft copolymerization. The critical amount of water to afford the maximum grafting yield was evaluated. The effect of the comonomer composition on the grafting yield was also investigated and it was observed that using a mixture of AAc/Sty monomers influences the extent of grafting of each monomer onto the PVA substrate and the phenomenon of synergism occurs during such a reaction. Also, the degree of grafting increases as the content of the solvent decreases in the reaction medium. However, the grafting yield increased as the total dose increased. The graft copolymer was characterized by IR and UV spectroscopic methods. The permeation of heavy metals such as Ni and Co through the grafted membranes was investigated and the efficiency of the separation process was also determined.

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“…Organofunctional groups with sulfur as the donor atom in order to adsorb mainly heavier metal ions from solution have also been immobilized on the silica gel surface. [11][12][13][14][15] These materials have been prepared in order to obtain adsorbents having the following characteristics: good sorption capacity, chemical stability under conditions of use, and especially, high selectivity.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a silica gel modified with 2-amino-1,3,4-thiadiazole for adsorption of metal ions and electroanalytical application

Filho¹,

Caetano²,

Carmo³

et al. 2006

J. Braz. Chem. Soc.

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Uma silica gel, com área específica de 382 m 2 g -1 e diâmetro médio de poro de 60 Å, foi modificada quimicamente com 2-amino-1,3,4-tiadiazol, com o propósito de adsorção seletiva de íons de metais pesados e possível utilização como um eletrodo de pasta de carbono quimicamente modificado (CMCPE). São discutidas as seguintes propriedades desta sílica gel funcionalizada: adsorção seletiva de íons de metais pesados, medida pelas técnicas "batch" e coluna cromatográfica, e utilização como agente de preconcentração em um eletrodo de pasta de carbono quimicamente modificado (CMCPE), para determinação de mercúrio(II). A seletividade química deste grupo functional e a seletividade da voltametria foram combinadas para preconcentração e determinação.Silica gel with a specific area of 382 m 2 g -1 and an average pore diameter of 60 Å was chemically modified with 2-amino-1,3,4-thiadiazole, for the purpose of selective adsorption of heavy metals ions and possible use as a chemically modified carbon paste electrode (CMCPE). The following properties of this functionalized silica gel are discussed: selective adsorption of heavy metal ions measured by batch and chromatographic column techniques, and utilization as preconcentration agent in a chemically modified carbon paste electrode (CMCPE) for determination of mercury(II). The chemical selectivity of this functional group and the selectivity of voltammetry were combined for preconcentration and determination.

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Removal of heavy metal ions from aqueous solutions using dithiooxamides supported on silica gel

Cited by 7 publications

References 5 publications

Chromatographic Separations with Selected Supported Chelating Agents

Chromatographic Separations with Selected Supported Chelating Agents

Preparation of poly(vinyl alcohol) grafted with acrylic acid/styrene binary monomers for selective permeation of heavy metals

Preparation of a silica gel modified with 2-amino-1,3,4-thiadiazole for adsorption of metal ions and electroanalytical application

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