Kinetics and thermodynamics of malachite green dye adsorption from aqueous solutions on graphene oxide and reduced graphene oxide

摘要

Rapid adsorption process of hazardous malachite green (MG) dye from the liquid phase onto the developed adsorbent i.e. graphene oxide (GO) and reduced graphene oxide (rGO) surfaces was well studied and elucidated. The batch adsorption experiments were carried out in order to evaluate the optimized values of the influential parameters such as initial pH, contact time, and temperature. The obtained optimized values of pH, contact time and temperature was 3, 100 min and endothermic nature of the adsorption process. It was found that by increasing the pH value from 3 to 9, the removal of malachite green dye by the developed adsorbent i.e. GO and rGO was decreased. Additionally by increasing the temperature, the removal of noxious MG dye by GO and rGO adsorbents was increased, which directly indicates towards the endothermic nature of the adsorption process. The adsorption kinetic data of malachite green dye on GO and rGO surfaces was found to be well fitted and in good agreement with the pseudo-first-order kinetic model because of the low value of the chi-square statistic (chi(2)) and high value of the correlation coefficients (R-2). (C) 2015 Elsevier B.V. All rights reserved.