Equilibrium Studies on Adsorption of Cu(II) from Aqueous Solution onto Cellulose

Abstract

Cellulose, a natural polymer, was used as an adsorbent for the adsorption of Cu(II) ions from the aqueous solutions of copper sulfate pentahydrate (CuSO4·5H2O) at different temperatures and a fixed pH. The amount adsorbed increased with increasing concentration of Cu(II) ions; however, it did not differ significantly with temperature. The equilibrium times of adsorptions of Cu(II) ions at various temperatures were the same. Kinetics studies showed that the adsorption process obeyed the first-order reversible kinetic model. It was also determined that adsorption isotherms followed both Freundlich and Langmuir models. Furthermore, the thermodynamic parameters, i.e., standard free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°), of the adsorption process were calculated. The results obtained are discussed in detail.