Thermodynamics and Kinetic Studies for the Adsorption Process of Methyl Orange by Magnetic Activated Carbons

This study investigates the adsorption behavior of methyl orange (MO) by magnetic activated carbons (MACs) with different ratios of AC: Magnetite from aqueous solution. Batch experiments for MO adsorption were carried out for evaluating the thermodynamics and kinetics parameters onto the MAC adsorbents. Variables such as pH, initial concentration of the dye, contact time, and temperature have been analyzed. The physicochemical characteristics of MACs were analyzed by scanning electron microscopy (SEM), surface area analyzer (BET), and X-ray power diffraction. The results of SEM and BET analysis showed that MAC adsorbents present a porous structure and large surface area, suitable conditions for the adsorption process. The X-ray diffraction patterns of MACs revealed that the adsorbents possess magnetite as magnetic material. Adsorption kinetic studies carried out onto MACs showed that the pseudo-second-order model provides a good description of the kinetic process. The adsorption equilibrium results were well adjusted to the Langmuir isotherm, showing that the maximum adsorption capacity was for MACs with a ratio 3:1 and 2:1 AC/magnetite. Thermodynamic analysis declares that the adsorption process was established as spontaneous, endothermic, and physical adsorption in nature. The results of the this study indicated that MAC adsorbents can be used successfully for eliminating MO from aqueous solution.