Characterization of zinc oxide nanorods loaded on activated carbon as cheap and efficient adsorbent for removal of methylene blue

In this research, zinc oxide nanoparticles loaded on activated carbon (ZnO-NRs-AC) synthesized in the presence of ultrasonic power and efficiently applied for removal of methylene blue (MB) from wastewater. Optimization of variables such as pH, concentration of MB, amount of ZnO-NRs-AC, contact time and temperature make permits to achieve maximum removal percentages in mild condition. Subsequently, the experimental equilibrium data at different concentration of MB and various amount of adsorbent mass was fitted to conventional isotherm models like Langmuir, Freundlich and Tempkin and it was revealed that the Langmuir is best model for explanation of behavior of experimental data. Following the effect of contact time on the adsorption rate was estimated and observed that experimental data can be represented by second order and interparticle diffusion model. The obtained negative value of Gibbs's free energy and positive value of adsorption enthalpy show the spontaneous nature and endothermic nature of adsorption process. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.