Gamma radiation induced preparation of organic-inorganic composite material for sorption of cesium and zinc

A novel composite material, poly(acrylamide-acrylic acid-acrylonitrile)-N, N′-methylenediacrylamide/silicon oxide-zirconium oxide [P(AM-AA-AN)-DAM/SiO2-ZrO2], was prepared by γ-radiationinduced template copolymerization of acrylic acid (AA) with acrylonitrile (AN) on polyacrylamide P(AM) as a template polymer in presence of N,N′-methylenediacrylamide (DAM) as cross-linker in aqueous solution with water-insoluble mixed oxide of silicon and zirconium. The composite material was characterized by Fourier transform IR spectroscopy and by thermal analysis (synchronized TGA-DTA). The sorption of 134Cs and 65Zn(II) onto the prepared composite material was investigated using batch equilibrium technique with variation of pH, adsorbent weight, initial sorbate concentration, contact time, and temperature. The sorption equilibrium data were fitted with the Langmuir and Freundlich isotherm models. The isotherm is successfully fitted by the Langmuir equation over the entire concentration range studied. Lagergren pseudo-first- and pseudo-secondorder kinetic models were tested to describe the reaction mechanism. The experimental data are fitted well the pseudo-second-order model. The thermodynamic functions (free energy ΔG 0, enthalpy ΔH 0, entropy ΔS 0) of the sorption were calculated. These quantities show that the sorption of 134Cs and 65Zn onto the composite material is spontaneous and endothermic. © 2014 Pleiades Publishing, Inc.