Chelate for-ming resins containing amino and thio groups have been prepared. The interaction of the obtained resins with Zn(II), Cd(II) and Hg(II) from their aqueous solutions was studied. The metal ion uptake behaviour and selectivity of the resins towards the metal ions were investigated by both batch and column methods. Hg(II) showed higher affinity towards the amino and the thio resins compared to Zn(II) or Cd(II). The mechanism of interaction between the resin and the studied metal ions could be explained on the basis of the formation of resin-metal complex in neutral conditions. In mediums acidified by HCI the interaction of Hg(II) was interpreted to proceed via ion-exchange mechanism. Hg(II) could be separated from Cd(II) in acidic medium. The studied resins were regenerated using HNO3 or acidified thiourea. It was not recommended to use HCI for elution of Hg(II) from the loaded resins due to its affinity for interaction with resins via ion-exchange. (C) 2003 Elsevier B.V. All rights reserved.