Evaluation of potato peel as a novel adsorbent for the removal of Cu(II) from aqueous solutions: equilibrium, kinetic, and thermodynamic studies

Abstract

In this study, potato peel (PP) was evaluated for its ability to remove Cu(II) ions from synthetic aqueous solutions under various operating conditions in a batch process. The effect of experimental parameters such as adsorbent dose (0.25–1.5), initial pH (2–5), stirring speed (0–800 rpm), temperature (25–55°C), ionic strength (0.25–5 g/400 mL), adsorbent particle size (0.16–1.5 mm), and initial Cu(II) concentrations (25–300 mg/L) on the removal of Cu(II) was investigated. The adsorption kinetics uptake for Cu(II) by PP at various initial metal ions concentrations was analyzed using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. It was found that the pseudo-second-order kinetic equation was the best applicable model to describe the adsorption kinetic data. The experimental data were analyzed by four adsorption isotherms, namely the Langmuir, Freundlich, Temkin, and Elovich models. Equilibrium data fitted well both to the Langmuir and Freundlich models with a maximum adsorption capacity of 84.74 mg/g at 25°C. Thermodynamic parameters of Cu(II) adsorption on PP have also been calculated. These results demonstrate that the PP is a suitable adsorbent for the removal of Cu(II) ions from aqueous solutions.