Novel chelating resins with aminothiophosphonate ligands

Metal chelating resins containing aminothiophosphonate ligands were synthes ised from two types of starting polymers: vinylbenzyl chloride/divinylbenze ne and more polar acrylonitrile/ethyl acrylate/divinylbenzene. Both polymer s were first modified with amines (ethylenediamine and diethylenetriamine) and subsequently reacted with diethyl thiophosphonochloridate. The resin ba sed on the more polar polymer, containing 2.61 mmol/g phosphorus and 5.52 m mol/g nitrogen, modified with ethylenediamine was selected as the most prom ising for Cd/Ni separation. Sorption studies have been performed with 10(-4 ) M Cd(II) and Ni(II) solutions in 0.2 M acetate buffer in the pH range 3.7 -5.6. It has been found that the aminothiophosphonate resin is highly speci fic for Cd (log K-d = 4-5), whereas Ni sorption is negligible. This new res in is compared with a commercial metal chelating polymer resin, Purolite S9 50, containing aminomethylphosphonate ligands. (C) 1999 Elsevier Science B. V. All rights reserved.