Study of Methylene Blue adsorption on keratin nanofibrous membranes

In this work, keratin nanofibrous membranes (mean diameter of about 220 nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16 kJ mol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudosecond-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters. (C) 2014 Elsevier B.V. All rights reserved.