Solvent-impregnated resins extraction process with

The use of impregnated resins or solvent-impregnated resins in extraction and recovery processes dates back to the pioneering work developed in the earlier 1970s by Warshawsky [1], Grinstead [2], and Kroebel and Meyer [3 and the topic has been thoroughly dealt with in some papers and reviews. Since the last review in 1981 [4] a whole series of important advances have been made. The present review has been written with the following objectives in mind ... 

An interesting property of resins impregnated with oximes or oxines is that the selectivity of, for example, copper over iron(III), approaches that of a pure solvent-extraction process only when an inert solvent is present in the pores of the resin.396 Thus, in a /S-hydroxyoxime SIR, the selectivity for copper over iron(III) improved by a factor of 20 when the solvent perchloroethylene was introduced into the SIR, and by a factor of 700 in a similar resin impregnated with 8-hydroxy-quinoline.396 This is believed to be due to kinetic and thermodynamic restrictions in the extraction of iron(III), but not of copper, at an aqueous—organic boundary.396 397... 

Ion-exchange resin methods, which are well known as useful preconcentration methods for trace ions, have some drawbacks slow adsorption and desorption rates, poor selectivity, and requirement for a concentrated solution of electrolyte such as acid, base, or neutral salts for recovery. Chromatographic methods in which solvent extraction procedures have been used in a continuous separation process using inert supports impregnated with the extractants combine many of the advantages of both liquid-liquid extraction and ion-exchange chromatography, which are the two of most im-... 

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