Adsorption of Cu(II) from synthetic wastewater employing chicken eggshell

Abstract

Adsorption of Cu(II) on Hydroxyapatite (HAp) derived from chicken eggshell by chemical precipitation method with H₃PO₄ was studied. Effective determinants of equilibrium contact time, initial concentration, and thermodynamic parameters to understand the nature of adsorption were investigated. Equilibrium contact time was found to be 210 min at an initial Cu(II) concentration of 200 mg/L, yielding an adsorption capacity of 32.19 mg/g. Freundlich, Langmuir and Temkin isotherms were used to fit the experiment data and the adsorption was best explained by the Freundlich isotherm. The Pseudo-second order kinetics model performed at 25°C and pH 6 was found to be more suitable than that of the first order. Eggshell HAp pellet adsorption capacity was finally compared with eggshell HAp powder and other commercial HAps; the best adsorption capacity at 115.9 mg/g was derived from eggshell HAp powder. Eggshell HAp pellet hence needs be further investigated on how to improve its adsorption capacity because of its requirement for convenience operations.