Analytica Chimica Acta 485 (2003) 213–219 Thorium(IV) and uranium(VI) sorption studies on octacarboxymethyl-C-methylcalix[4]resorcinarene impregnated on a polymeric support Nadir Demirel, Melek Merdivan ∗ , Necmettin Pirinccioglu, Candan Hamamci Department of Chemistry, Faculty of Science and Arts, Dicle University, 21280 Diyarbakir, Turkey Received 14 January 2003; received in revised form 4 March 2003; accepted 1 April 2003 Abstract The impregnation of octacarboxymethyl-C-methylcalix[4]resorcinarene into a polymeric matrix, Amberlite XAD-4, is reported and was characterized by infrared spectroscopy. The sorption capacity of the impregnated resin is 0.34×10 -3 mol g -1 . The resin was used for the sorption of thorium(IV) and uranium(VI) from aqueous solution. The properties of capacity, pH effect, and breakthrough curves of the impregnated resin were investigated. The capacity of the resin for Th(IV) and U(VI) was found to be 0.29 and 0.27 × 10 -3 mol g -1 , respectively. The metal ions were eluted with 0.4–2M HCl or HNO 3 . Chromatographic separation of Th(IV) and U(VI) was accomplished by adjustment of pH to 3.0 and 6.0, respectively. The impregnated resin exhibits a high chemical stability, reusability and fast equilibration. Separation of Th(IV) and U(VI) from other metal cations in synthetic solution was achieved. © 2003 Elsevier Science B.V. All rights reserved. Keywords: Calix[4]resorcinarene; Impregnated resin; Uranium(VI) and thorium(IV) 1. Introduction There is considerable interest in the behavior of actinides at trace levels in environmental and biolog- ical samples due to the increasing public attention to radioactive waste disposal and potential public health effects of releases of radioactive materials into the environment. Thorium and uranium are present in nuclear fuel and their determinations are of signifi- cance. Numerous methods have been described for their effective separation and preconcentration; proce- dures based on ion exchange [1,2], solvent extraction [3–5], and solid phase extraction [6–18] are among ∗ Corresponding author. E-mail address: merdivan@dicle.edu.tr (M. Merdivan). them. Solid phase extraction is now widely used for the preconcetration and clean up of various chemicals and for applications such as the removal of toxic or valuable substances from a variety of predominantly aqueous solutions. Chelating resins are of immense value for selective trace metal analysis. Appropriate chelating reagents can be chemically bonded to [6–10,19–21] or impreg- nated onto support matrices [13,14,17], thus provid- ing complexing or chelating solid phases. Amberlite XAD series resins have shown promise for designing chelating resins. Several previous studies have been reported for the XAD series resins in which an inert support is impregnated (e.g. bifunctional organophos- phorus [13], N,N-dibutyl-N ′ -benzoylthiourea [14], diamylphosphonate [17] or immobiilzed (e.g. 4-(2- 0003-2670/03/$ – see front matter © 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0003-2670(03)00415-X