Efficiency of Cd(II) removal from aqueous media using chemically modified polystyrene foam

The removal of Cd(II) using polystyrene foam chemically modified with 2,2'-bipyridine has been investigated. The modified polystyrene foam has been characterized by FT-IR spectroscopy, thermogravimetry, elemental analysis and scanning electron microscopy. The solid was employed as a Cd(II) adsorption from aqueous solutions at room temperature. The effects of several variables (pH, shaking speed, agitation time, metal concentration and presence of other ions in the medium) have been studied using batch technique. Flame atomic absorption spectrometry was used to determine the Cd(II) ion concentration in the filtrate after the adsorption process. Maximum sorption >= 90% was achieved at pH 7 after 30 min of shaking time. Sorbed metal ions have been desorbed with 5 ml of 2 M HNO3 with the detection limit of 16.7 ng ml(-1). The Langmuir, Freundlich and D-R isotherm equation were used to describe partitioning behavior of the system at room temperature. Kinetic and thermodynamic behavior of modified polystyrene foam for Cd(II) ion removal was also studied. Br-, PO43-, Pb2+, Ni2+ and Cr(VI) suppress the sorption to some extent. The possible sorption mechanism of Cd(II) ions onto modified sorbent is also discussed. Method was utilized to remove Cd(II) ions from aqueous media. (C) 2008 Elsevier Ltd. All rights reserved.