Synthesis, characterization and application of ethylenediamine functionalized chelating resin for copper preconcentration in tea samples

A novel ethylenediamine functionalized chelating resin (ED resin) with simple technology, high adsorption capacity and significant selectivity was synthesized. It was characterized by elemental analysis and infrared spectra, and was applied for determination of metal ion in tea samples. The optimized synthesis conditions is molar ratio ED:Cl = 2:1, 100 °C as reaction temperature and DMF as solvent. ED resin can be used in separating Cu(II) from aqueous solutions. The adsorption processes were evaluated by Langmuir and Freundlich isotherms. Pseudo-second-order kinetics showed better accordance. Thermodynamic parameters indicated that adsorption process was spontaneous and endothermic. Thomas model was applied to determine the characteristic parameters of column useful for process design. Finally, Cu(II) can be eluted by 1.0 mol L−1 HCl solution. AAS method was applied for copper determination after the pre-concentration step, and the results indicated that ED resin is essentially free from interferences, which can contribute to accurate determination in waters and foods.

► A novel ethylenediamine chelating resin for adsorption has been synthesized and well characterized.
► It showed higher affinity towards Cu(II) compared to Ni(II), Cd(II), Co(II), Zn(II) or Pb(II).
► It can be regenerated effectively using 1.0 mol L−1 HCl solution without any adsorption capacity decrease.
► It was employed for selective separation and preconcentration of Cu(II) ions in waters and foods.