The Pre-concentration and determination of Iridium and Palladium in environmental water by imprinted polymer-based metho

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ORIGINAL PAPER

The Pre-concentration and determination of Iridium and Palladium in environmental water by imprinted polymer-based method H. Sid kalal • M. Taghiof • H. Hoveidi • N. Pakizvand • H. Vahidi • H. A. Panahi S. Tavangari



Received: 6 October 2012 / Revised: 6 April 2013 / Accepted: 23 April 2013 / Published online: 23 May 2013 Ó Islamic Azad University (IAU) 2013

Abstract In this study, the imprinted aniline–formaldehyde was used as an adsorbent for removal of Iridium and Palladium ions from aqueous solutions through batch equilibrium. The sorbent was characterized by fourier transform infrared spectroscopy. The influence of pH, equilibrium time, temperature and initial concentration of metal ions on adsorbed amount of both ions were investigated. The maximum adsorption capacity in initial concentration of 100 mg/L was found to be 12.5 mg/g at pH 7.0 and 14.3 mg/g at pH 8.0 for Iridium and Palladium, respectively. In addition, the best desorption of the metal ions from resin was obtained by 0.5 mol/L nitric acid as eluting agent. The profile of both ions uptake on this sorbent reflects good accessibility of the chelating sites in the imprinted aniline–formaldehyde. Langmuir, Freundlich, Temkin and Redlich–Peterson isotherm models were applied to analyze the experimental data. Moreover, Langmuir linear method was used to obtain the isotherm parameters. However, Langmuir type II achieved the highest coefficient which led to the best fit for the palladium and the best fit for Iridium obtained from linear Redlich–Peterson. However, the thermodynamic parameters (DG°, DH°, and DS°) were also determined using the

H. Sid kalal (&)  M. Taghiof  N. Pakizvand NFCRS, Nuclear Science and Technology Research Institute, AEOI, P.O. Box 11365-3486, Tehran, Iran e-mail: [email protected] H. Hoveidi  H. Vahidi Graduate Faculty of Environment, University of Tehran, Tehran, Iran H. A. Panahi  S. Tavangari Department of Chemistry, Islamic Azad University, Central Tehran Branch, Tehran, Iran

equilibrium constant values obtained at different temperatures. The results showed that the adsorption for Iridium and Palladium ions was spontaneous nature and endothermic. Moreover, the method was applied for the determination of both ions from tap water samples. Keywords Adsorption isotherms  Error analysis  Kinetic studies

Introduction Palladium is a rare and lustrous silvery white metal and was discovered in 1803 by William Hyde Wollaston. Palladium, platinum, rhodium, ruthenium, Iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has less melting point and dense. Moreover, the unique properties of palladium and other platinum group metals account for their widespread usage. A quarter of all goods manufactured today either contains PGMs or have a significant part in their manufacturing process played by PGMs (Lide and Frederikse 1995). Moreover, Palladium is found in many electronics such as computers, mobile phones, multi-laye