Removal of copper from aqueous solution using newspaper pulp as an adsorbent

Abstract

Newspaper pulp was found to be a potential adsorbent for removal of copper from aqueous medium. Detail adsorption study of Cu on newspaper pulp was investigated. Batch adsorption study was carried out as a function of contact time, adsorbent dose, temperature (303–323 K). The experimental data was analyzed using Freundlich, Langmuir, Dubinin–Radushkevich (D–R) and Redlich-Peterson (R–P) isotherm models. It was found that Freundlich, Langmuir and R–P models fitted well. pH variation study revealed that the adsorption increased with increase in pH of the solution. Maximum loading capacity was found to be 30 mg g−1 at 20 mg L−1 of initial Cu concentration. Adsorption data were analyzed using two kinetic models, Lagergren first order and pseudo second order. It was observed that pseudo second order represented the best correlation. Langmuir isotherm was used to obtain the thermodynamic parameters such as free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption. The negative value of free energy and positive value of enthalpy change indicate that the adsorption of Cu on newspaper pulp is a spontaneous process and endothermic. The results of activation energy also confirmed that the adsorption of Cu on newspaper pulp is physical in nature. Present investigation emphasized that newspaper pulp may be utilized as a low cost adsorbent for copper removal.