The adsorptive removal of MB using chemically treated artichoke leaves: Parametric, kinetic, isotherm and thermodynamic study

Abstract

In this paper, we are interested in developing techniques for water discoloration and exploiting agriculture wastes as biosorbents. For that we studied the adsorption mechanism of methylene blue (MB) on chemically treated artichoke leaves (T-AL). To understand the adsorption process of the system Dye/T-AL various studies were performed. Parametric studies of MB adsorption with and without different salts were carried out using the Response Surface Methodology (RSM). The obtained results showed that the adsorption of MB alone (mono-system) is mainly related to pH and adsorbent dose. In the presence of salts, the adsorption efficiency of MB is principally linked to the pH of the solution and the initial concentration of salts. Even the nature of salts influences the capacity of MB adsorption. The kinetic data were analyzed using different models. It was observed that the pseudo-second-order model was the best model describing the adsorption behavior of MB onto (T-AL) in the mono-system (Dye/T-AL), bi-system, (Dye; Salt)/T-AL and mixed system with different salts (Dye; ΣMixed Salts)/T-AL. By analyzing the adsorption isotherm data, it was found that the MB adsorption in all studied systems is better suited to the Langmuir model. Furthermore, the values of thermodynamic parameters ΔG°, ΔH°, and ΔS° indicate that the interaction is thermodynamically favorable and that the adsorption mechanism is exothermic with physical nature.