Title
Adsorption of Cu(II) from aqueous solution on wheat straw lignin: Equilibrium and kinetic studies
Authors
TATIANA TODORCIUC LAURA BULGARIU and VALENTIN I. POPA

Received January 4, 2014
Published Volume 49 Issue 5-6 May-June
Keywords wheat straw lignin, Cu(II), adsorption, equilibrium, kinetics

Abstract
In this study, the adsorption of Cu(II) ions from aqueous solutions onto wheat straw lignin was investigated. The experiments were performed in a batch system, at room temperature (20 ± 0.5 °C), and the copper ions analysis was done after equilibrium was attained. Different experimental parameters (initial solution pH, sorbent dose, initial Cu(II) concentration and contact time) were varied in order to establish the optimum conditions for copper removal using wheat straw lignin. The experimental results were fitted using the Langmuir, Freundlich and Sips isotherm models, and the characteristic adsorption parameters were determined. Experimental data were also tested using two kinetic models: the pseudo-first-order Lagergren model and the pseudo-second-order Ho model. Based on these models, the kinetic parameters (rate constant and equilibrium adsorption capacity) for Cu(II) adsorption on lignin were calculated.