Chelating ion exchange resins

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. 

According to Gregor et al.35 the following properties are required for a chelating agent which is to be incorporated as a functional group into an ion exchange resin  

the chelating agent should yield, either alone or with a cross-linking substance, a resin gel of sufficient stability to be capable of incorporation into a polymer matrix  

the chelating group must have sufficient chemical stability, so that during the synthesis of the resin its functional structure is not changed by polymerisation or any other reaction  

the steric structure of the chelating group should be compact so that the formation of the chelate rings with cations will not be hindered by the resin matrix. 

CS3 10 pm substrate coated with 50 nm aminated latex and then with 250 nm sulfonated 

CS5A Bifunctional pellicular, both catex and anex functions. Highly cross-linked 

CSIO Aminated colloidal polymer layer covalently bound to substrate of high cross-linking. 

100 % solvent stability, moderate capacity, hydrophilic surface 

CS12 Has a thin polymer layer with carboxyl groups grafted to a polymeric substrate 

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New chelating ion-exchange resins are able to selectively remove many heavy metals in the presence of high concentrations of univalent and divalent cations such as sodium and calcium. The heavy metals are held as weaMy acidic chelating complexes. The order of selectivity is Cu > Ni > Zn > Co > Cd > Fe + > Mn > Ca. This process is suitable for end-of-pipe polishing and for metal concentration and recovery. 

CONCENTRATION OF COPPER(II) IONS FROM A BRINE SOLUTION USING A CHELATING ION EXCHANGE RESIN... 

E Blasius and B Brozio, Chelating ion-exchange resins. In Chelates in Analytical Chemistry, H A Flaschka and A J Barnard (Eds), Vol. 1, Marcel Dekker, New York, 1967, p 49... 

Chelating ion-exchange resins. E. Blasius and B. Brozio, Chelates Anal. Chem., 1967, 1, 49-79 (149). 

Horwitz EP, Chiarizia R, Dietz ML, Diamond H, Nelson DM (1993a) Separation and preconcentration of actinides from acidic media by extraction chromatography. Anal Chim Acta 281 361-372 Horwitz EP, Chiarizia, R., Diamond H, Gatrone RC, Alexandratos SD, Trochimzuk AQ, Crick DW (1993b) Uptake of metal ions by a new chelating ion exchange resin. 1. Acid dependencies of actinide ions. Solvent Extr Ion Exch 11 943-966... 

Lloyd-Jones, P.J., Rangel-Mendez, J.R., and Streat, M., Mercury sorption from aqueous solution by chelating ion exchange resins, activated carbon and a biosorbent, Process Safety and Environmental Protection, 82 (4), 301-311, 2004. 

According to the developer, HISORB ion exchange material is less expensive than the more common chelating ion exchange resins (D161780, p. 356 D17038H, p. 2195). 

Chelex 100 and Qrelex 220 Chelating Ion exchange Resin Instmchon Manual, http // www.biorad.com/webmaster/pdfs/9184 Chelex.PDF) (accessed 26 May 2012). 

Schwartz, A., Marinsky J. A., and Spiegler, K. S. (1964). Self-exchange measurements in a chelating ion-exchange resin. J. Phys. Chem. 68, 918. 

Depending on the position of metal with respect to the main chain, PCMU can be subdivided into two distinct classes. Polymeric chelates whose main chain contains a metal and which breaks upon its removal are termed coordination polymers. They have been exhaustively described elsewhere [7]. The second class of PCMU which is discussed in this review contains metal in a side chain. In this case the metal can be fairly readily removed or displaced by other metals so that the main chain remains intact. Such PCMU actually incorporate complexes of metals with chelating ion-exchange resins [8]. 

Yoshida, I., Ueno, K. and Kobayashi, H., Selective separation of arsenic (III) and (V) ions with ferric complex of chelating ion-exchange resin, Sep. Sci. 13, 173-184 (1978). 

An attractive approach to the removal of interferents involves the use of the chelating ion-exchange resin Chelex 100. With the exception of iron(Il) and iron(III), all identified cationic interferents can be overcome by passing the sample solution (at pH 4.0) through a column of this resin. The ubiquitous nature of iron, however, precludes the application of this procedure in most practical circumstances. 

J. Melling and D. West, A Comparative Study Of Some Chelating Ion Exchange Resins For Applications In Hydrometallurgy , in Ion Exchange Technology , ed. D. Naden and M. Streat, Ellis Horwood, Chichester, 1984, p. 724. 

The chelating ion-exchange resins Chelex-100 and Permutit S 1005 completely retain vanadium [Sc, Ni, Cu, Zn, Y, Mo, Ag, Cd, In, rare earths, W, Re (90%), Pb, Bi, and Th] from sea water. Manganese is retained quantitatively only by the Chelex resin. Vanadium (Mo, W, Re) is removed from the resins with 4N ammonia, the other metals with 2 N mineral acids 56). Both resins consist of a cross-linked polystyrene matrix with iminodiacetic acid [—CH2—N(CH2COOH)2] functional groups. Alkali and alkaline earth metals do not form chelates with iminodiacetic acid except at very high pH, whereas many transition metal ions form 1 1 complexes. 

The counterion that interacts more strongly with the fixed ionic groups or with the matrix. The former is the basis for chelating ion exchange resins and many other specialty resins and is explained in detail in the subsequent section. The interaction of the counterion with the... 

Table 1 Salient information on some chelating ion exchange resins...

Price, S.G. Helditch, D.J. Streat, M. Diffusion or chemical kinetics control in a chelating ion exchange resin system. In Ion Exchange for Industry Streat, M., Ed. Ellis Horwood Ltd. Chichester, U.K., 1988. 

R. R. Grinstead, Selective Absorption of Copper, Nickel, Cobalt and Other Transition Metal Ions from Sulfuric Acid Solutions with the Chelating Ion Exchange Resin XFS4195, Hydrometallurgy, 12, pp. 387-400 (1984). 

Kinetics of Removal of Heavy Metals by a Chelating Ion-Exchange Resin... 

The successful use of chelating ion exchange resins to treat metal plating baths depends upon the selective sorption properties of the resins for the ions present in the plating baths. The selectivity of the sorption can depend upon a number of factors, including the temperature, pH, and upon the type and concentration of other anions and cations present in the solution. Various competing ion effects have been noted for metals such as copper, nickel, cobalt, iron, zinc and others (4 - 8). 

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