SYNTHESIS AND CHARACTERIZATION OF A BIFUNCTIONAL ION-EXCHANGE RESIN WITH POLYSTYRENE-IMMOBILIZED DIPHOSPHONIC ACID LIGANDS

A new ion exchange resin for the selective complexation of metal ions has been synthesized by functionalizing vinylbenzyl chloride-styrene-d ivinylbenzene copolymer beads with the sodium salt of tetra(isopropyl) methylene diphosphonate. The effects of bifunctionality, matrix rigid ity, degree of functionalization, and macroporosity on final resin pro perties have been quantified. A sulfonic acid-diphosphonic acid bifunc tional resin is highly selective with rapid complexation kinetics. A m acroporous polymer matrix crosslinked with 10% divinylbenzene provides optimum results; for example, 99.7% Eu(III) is complexed from a IM ni tric acid solution with a 30-min contact time. The importance of physi cal crosslinking as well as chemical crosslinking in limiting access o f substrates into polymer-supported reagents is discussed. (C) 1996 Jo hn Wiley & Sons, Inc.