Template polymerization synthesis of hydrogel and silica composite for sorption of some rare earth elements E.H. Borai a , M.G. Hamed a,⇑ , A.M. El-kamash a , T. Siyam a , G.O. El-Sayed b a Hot Laboratories Center, Atomic Energy Authority, 13759, Egypt b Chemistry Department, Benha University, Egypt graphical abstract article info Article history: Received 6 April 2015 Accepted 11 June 2015 Available online 17 June 2015 Keywords: Polymer Adsorption Rare earth elements abstract New sorbents containing 2-acrylamido 2-methyl propane sulphonic acid monomer onto poly(vinyl pyrilidone) P(VP-AMPS) hydrogel and P(VP-AMPS-SiO 2 ) composite have been synthesized by radiation template polymerization. The effect of absorbed dose rate (kGy), crosslinker concentration and polymer/- monomer ratio on the degree of template polymerization of P(VP-AMPS) hydrogel was studied. The degree of polymerization was evaluated by the calculated percent conversion and swelling degree. The maximum capacity of P(VP-AMPS) hydrogel toward Cu +2 metal ion found to be 91 mg/gm. The polymeric composite P(VP-AMPS-SiO 2 ) has been successfully synthesized. The structure of the prepared hydrogel and composite were confirmed by FTIR, thermal analysis (TGA and DTA) and SEM micrograph. Batch adsorption studies for La 3+ , Ce 3+ , Nd 3+ , Eu 3+ and Pb +2 metal ions on the prepared hydrogel and composite were investigated as a function of shaking time, pH and metal ion concentration. The sorption efficiency of the prepared hydrogel and composite toward light rare earth elements (LREEs) are arranged in the order La 3+ > Ce 3+ > Nd 3+ > Eu 3+ . The obtained results demonstrated the superior adsorption capacity of the composite over the polymeric hydrogel. The maximum capacity of the polymeric composite was found to be 116, 103, 92, 76, 74 mg/gm for La 3+ , Ce 3+ , Nd 3+ , Eu 3+ and Pb 2+ metal ions respectively. Ó 2015 Elsevier Inc. All rights reserved. 1. Introduction One of the commonly used methods for modifying the surface and bulk properties of polymeric materials is to template http://dx.doi.org/10.1016/j.jcis.2015.06.020 0021-9797/Ó 2015 Elsevier Inc. All rights reserved. ⇑ Corresponding author. Journal of Colloid and Interface Science 456 (2015) 228–240 Contents lists available at ScienceDirect Journal of Colloid and Interface Science journal homepage: www.elsevier.com/locate/jcis