Resins chelating

The introduction of chelating functional groups (e.g. amino diacetate) into polymer beads yields a product with a high affinity for metal ions, but also capable of excluding large molecules and colloidal particles from the inner pores (i.e. in some situations the column can act as a size differentiation medium) (Florence, 1977). Compared with other techniques (such as dialysis, ultra-filtration and solvent extraction), chelating column separations can be claimed to be faster and simpler, with the equipment being relatively less expensive. 

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Chelex 100 0.4 0.65 Weakly acidic chelating resin with S-DVB... 

A problem common to produced water appHcations is the tendency for oil fouling of the resin. If weak acid or chelate resins are used, a two-step regeneration process is required which uses acid to remove calcium and magnesium from the resin, foUowed by a dilute NaOH solution to convert the resin to the sodium form. 

Many attempts have been made to reduce the ammoniacal and sulfurous odor of the standard thioglycolate formulations. As the cosmetics market is very sensitive to the presence of impurities, odor, and color, various treatments of purification have been claimed to improve the olfactory properties of thioglycolic acid and its salts, such as distillation (33), stabilization against the formation of H2S using active ingredients (34), extraction with solvents (35), active carbon (36), and chelate resin treatments (37). 

Other developments in chelating resins include fibers made from poly(ethylene glycol) and poly(vinyl alcohol) to which EDA was attached with epichl orohydrin (281) and a styrene—divinylbenzene resin with pendant EDTA or DETPA groups (282). 

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. 

Chelating resins Duolite ES466 Amberlite 718 Chelex 100... 

The exchange process in a chelating resin is generally slower than in the ordinary type of exchanger, the rate apparently being controlled by a particle diffusion mechanism. 

The starting material for the synthesis of this chelating resin is chloromethylated styrene-divinylbenzene, which undergoes an amination reaction and is then treated with monochloracetic acid ... 

In contrast to the above resins, the chelating resin Amberlite IRC-718 is based upon a macroreticular matrix. It is claimed to exhibit superior physical durability and adsorption kinetics when compared to chelating resins derived from gel polymers and should also be superior for use in non-aqueous solvent systems. 

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. 

G Schmuckler, Chelating resins — Their analytical properties and applications Talanta, 1965, 12, 281... 

Chelate effect 54 Chelates 161, 169, 237 for gas chromatography, 237 Chelating resins 202, 212 Chelation 52... 

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... 

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