Kinetic and thermodynamic study of the adsorption isotherm of methylene blue dye from aqueous solutions by activated carbon

The efficiency of activated carbon in wastewater as a powerful blue dye remover has been studied. In this work, activated carbon manufactured from Sidr leaves was used to adsorb methylene blue dye. The factors affecting adsorption were studied, such as the weight of the adsorbent, temperature, contact time, and initial concentration of the dye, and the optimal conditions for adsorption were determined according to the experimental results. It was evident from the experimental results obtained that the removal efficiency increases with the increase of both the weight of the adsorbent material and the contact time. It was observed that the adsorption process was possible, spontaneous, and exothermic in the temperature range (293-333 K), and this is what determined the thermodynamic variables ΔG°, ΔH°, and ΔS°. The Langmuir, Freundlich, and Timken isotherms were used to examine the experimental equilibrium data. To follow the adsorption process, two logical models were chosen, represented by the Elovage equation and diffusion.