Copper removal from aqueous systems with coffee wastes as low-cost materials

Abstract

This work aims to study the removal of Cu(II) from aqueous solutions with coffee residues. Waste materials with no further treatment such as coffee residues from café may act as adsorbents for the removal of Cu(II). Equilibrium data were successfully fitted to the Langmuir, Freundlich and Langmuir-Freundlich model (L-F). The maximum adsorption capacity of the coffee residues can reach 70 mg/g for the removal of Cu(II). The kinetic data were fitted to pseudo-first, -second and -third order equation. The equilibrium was achieved in 120 min. Also, the effect of pH on adsorption and desorption was studied. Ten cycles of adsorption-desorption were carried out revealing the strong reuse potential of these low-cost adsorbents; the latter was confirmed from a brief economic approach.