Synthesis and application of Alizarin red S bonded polyurethane foam for separation and preconcentration of trace amounts of some metal ions in wastewater

Abstract

Chemistry Department, Faculty of Science, Mansoura University, Damietta, Egypt E-mail : [email protected] Manuscript received 14 January 2003, revised 26 September 2003. accepted 17 November 2003 A stable chelating resin matrix was prepared by covalently linking Alizarin red S with polyurethane foam, through a -N=N group, and identified through UV/Vis and IR. The resin was used in batch and column techniques for the separation and prcconcentration of Ag^I, Hg^II and Pb^II from wastewater. The various parameters affecting the retention efficiency of the tested metal ions from aqueous media by the Alizarin red S bonded polyurethane foam (AI-Puf) were examined, e.g. pH, contact time, sorption isotherm, flow rate and breakthrough capacity. Extraction was accomplished during 5-15 min at pH 9, 2-4 and 4-6 for Ag^I, Hg^II and Ph^ll, respectively. The capacities of AI-Puf were 4.2, 2.5 and 2.4 mmol/g for Ag^I, Hg^II and Pb^II , respectively. The detection limit was about 4 ng/ml for preconcentration factor of 50 has been achieved (rsd - 3.46% ). The kinetics and thermodynamics of the sorption of the tested ions onto AI-Puf have been studied. The sorption of Ag^I, Hg^ll and Pb^II onto Al-Puf follow a first order rate equation, with the rate constant, k, to be 0.211, 0.448 and 0.207 mim^-1, respectively. The values of Gibbs free energy (∆G) for the sorption of Ag^I, Hg^ll and Pb^II were -4.29, -2.73 and -3.43 kJ mol^-1, respectively at 298 K. The proposed method has been successfully applied to the assay of tested metal ions in waste - water.