Wool Keratin Nanofibres for Copper(II) Adsorption

In this study, mats made of randomly oriented pure keratin nanofibres (∼400 nm diameter) were prepared by electrospinning and tested for Cu2+ adsorption. Batch adsorption tests were carried out at pH 6, with different Cu2+ concentrations and contact times. The adsorption capacity and the removal efficiency are higher than those of conventional wool fabrics. This behaviour is due to the higher specific surface area of the nanofibres. By using an adsorbent dosage (mass of adsorbent/volume of the solution) of 1 g/L, the maximum adsorption capacity was 20 mg/g. The adsorption isotherm of the nanofibre mats fitted the Langmuir equation and the separation factor (RL, calculated to evaluate the adsorption efficiency, falls between 0 and 1 denoting a favourable adsorption. The mean free energy adsorption (E) evaluated applying the Dubinin-Radushkevich model is 12.9 kJ/mol, proving that electrostatic interactions are potentially involved in the sorption process.