SYNTHESIS OF BIFUNCTIONAL ION-EXCHANGE RESINS THROUGH THE ARBUSOV REACTION - EFFECT ON SELECTIVITY AND KINETICS

Bifunctional ion-exchange resins are synthesized from vinylbenzyl chlo ride-styrene copolymers. The two types of functional groups are introd uced by an Arbusov reaction followed by sulfonation. The effect of lig and ratios, macroporosity, and matrix rigidity on the complexation of Eu(III) from solutions of low pH is quantified. It is found that ion c omplexation kinetics and selectivity are maximized with resins having both sulfonic and phosphonic acid ligands. Maximum metal ion complexat ion rates depend on a balance between chemical interactions (i.e., a b ifunctional network interacting with a given substrate through an acce ss and a recognition mechanism) and physical parameters (i.e., matrix porosity and rigidity). Structural integrity must be maintained throug h an appropriate crosslink level in order for the advantage of bifunct ionality to be maintained in low-pH solutions. (C) 1994 John Wiley & S ons, Inc.