Resin metal chelating

Ecoscope Hexane (organics) chelating resin (metals) Polyethylene membrane (organics), porous membrane (metals) Hydrophobic organic compounds, heavy metals Qualitative screening 2-4 weeks Direct injection of solvent or after concentration or extraction with acid 59... 

Ligand exchange Equihbrium Chromatographic separation of glucose-fructose mixtures with Ca-form resins Removal of hea y metals with chelating resins Affinity chromatography... 

The cost of resins is a major consideration. Heavy-metal-selective chelating resins are the most expensive. Table 4 provides some cost ranges for commercially available resins. 

Theory. Conventional anion and cation exchange resins appear to be of limited use for concentrating trace metals from saline solutions such as sea water. The introduction of chelating resins, particularly those based on iminodiacetic acid, makes it possible to concentrate trace metals from brine solutions and separate them from the major components of the solution. Thus the elements cadmium, copper, cobalt, nickel and zinc are selectively retained by the resin Chelex-100 and can be recovered subsequently for determination by atomic absorption spectrophotometry.45 To enhance the sensitivity of the AAS procedure the eluate is evaporated to dryness and the residue dissolved in 90 per cent aqueous acetone. The use of the chelating resin offers the advantage over concentration by solvent extraction that, in principle, there is no limit to the volume of sample which can be used. 

Acetic acid, ethylenenitrilo[(hydroxyethyl)nitrilo]tri-iron(III) complexes, 2,788 Acetic acid, hexamethylenediaminetetra-synthesis, 2,779 Acetic acid, iminodi-chelating resins mineral processing, 6,824 metal complexes, 1,554 2, 788... 

Dithiobenzoic acid metal complexes, 2, 646 colours, 2, 646 Dithiobiuret metal complexes, 2, 640 Dithiocarbamates chelating resins mineral processing, 6,826 Dithiocarbamic acid metal complexes, 2,585 amine exchange, 1,428 photographic emulsions, 6,98 nickel poisoning, 6,768 tellurium(Il) complexes photothermography, 6,121 Dithiocarbazic acid metal complexes, 2,803 Dithiocarbimic acid metal complexes, 2,588 Dithiocarbimic acid, cyano-metal complexes, 2,808 Dithiocarboxylic acids metal complexes, 2,646 Dithiodiacetic acid metal complexes, 2, 806 Dithiodiketones... 

Polyisothiouronium group chelating resins mineral processing, 6,826 Polyketones metal complexes, 2, 399 Poly(L-lysine) metal complexes, 2, 764 Polymerization solid state, 1, 470 Polymers... 

PS DVB -CH2N(CH2COONa)2 Chelate resins exchanged with metal ions... 

Gardner and Yates [26] developed a method for the determination of total dissolved cadmium and lead in estuarine waters. Factors leading to the choice of a method employing extraction by chelating resin, and analysis by carbon furnace atomic absorption spectrometry, are described. To ensure complete extraction of trace metals, inert complexes with humic-like material are decomposed by ozone [27]. The effect of pH on extraction by and elution from chelating resin is discussed, and details of the method were presented. These workers found that at pH 7 only 1-2 minutes treatment with ozone was needed to completely destroy complexing agents such as EDTA and humic acid in the samples. 

Three methods for trace metal preconcentration were examined liquid-liquid extraction aided by a chelating agent, concentration on a synthetic chelating resin and reductive precipitation with NaBTLt. The latter method gave 1000-fold preconcentration factors with total recovery of Pb and other elements17. Preconcentration of nanogram amounts of lead can be carried out with a resin incorporating quinolin-8-ol (3)18. Enhancement factors of 50-100 can be achieved by such preconcentration procedures followed by determination in a FLA (flow injection analysis) system limits of detection are a few pg Pb/L19. 

Resins can also be prepared with chelating functional groups which show selective affinities for certain metals. Iminodiacetic acid, vinylacetylacetone, glyoxal-thiophenol and 8-hydroxy quinoline have all been used to produce these so-called chelating resins. Their selectivities are similar to those of the free reagent. 

Uses. Hardener/cross-linker for epoxy resins metal chelator constituent of wet-strength paper resins copolymer with fatty acids in metal spray coatings constituent of synthetic elastomer formulations... 

Florence TM, Batley GE. Trace Metal Species in Sea Water-I. Removal of Trace Meals from Seawater by a Chelating resin. Tantala 1976 23 179. 

In Table 4.13, the relative selectivity of a commercial chelating resin for heavy metal cations is shown. The relative selectivity is based on the selectivity for calcium ions. For... 

In Figure 4.11, the formula of a chelating resin is shown with the iminodiacetic acid group as the chelating ligand, which is bonded onto a cross-linked polystyrene matrix. This type of resin shows a large affinity for alkaline-earth and transition metal ions. 

Poly(ethyleneimine)(PEI) bridged by alkylene dihalide has been used as a chelating resin for Cu and Co68. Dingman et al,69 studied the adsorption of metal ions on PEI resins crosslinked with toluene diisocyanate. The amount of metal ions adsorbed decreases with the degree of crosslinking. These crosslinked PEI resins... 

Such adsorption behavior of a chelating resin is schematically illustrated in Fig. 15(b), where the binding ability of the resin varies with pH. In contrast to Fig. 15(b), if the adsorption capacity is adjusted for each metal ion, i.e. (he ordinate... 

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