Glutaraldehyde cross-linked epoxyaminated chitosan as an adsorbent for the removal and recovery of copper(II) from aqueous media

A novel glutaraldehyde cross-linked epoxyaminated chitosan (GA-C-ENCS) prepared through chemical modification was used as an adsorbent for the removal and recovery of Cu(II) from aqueous media. The adsorbent was characterized by FTIR, SEM-EDS, ESR, TG/DTG, BET-surface area and potentiometric titration. The Cu(II) adsorption process, which was pH dependent showed maximum removal at pH 6.0. Adsorption equilibrium was achieved within 3 h. The adsorption of Cu(II) followed a reversible-first-order kinetics. The equilibrium data were evaluated using the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The best interpretation for the equilibrium data was given by the Dubinin–Radushkevich isotherm. The adsorption capacity of the adsorbent increased from 3.11 to 3.71 mmol g⁻¹ when the temperature was increased from 20 to 50 °C. The complete removal of 20.7 mg L⁻¹ Cu(II) from electroplating industry wastewater was achieved by 0.4 g L⁻¹ GA-C-ENCS. Regeneration experiments were tried for four cycles and the results indicate a capacity loss of <7.0%.