RSM optimized adsorptive removal of erythromycin using magnetic activated carbon: Adsorption isotherm, kinetic modeling and thermodynamic studies

Erythromycin molecules are resistant in the environment due to the structure of its aromatic-ring that makes it hard to remove or degradation. Nowadays, the presence of ERY in water and wastewater has been reported are above the standard level in various researches. Therefore, the removal and degradation of residues of ERY from wastewaters is important. The magnetic activated carbon is fabricated from Gogan almond shells and characterized and then applied to removal erythromycin from wastewater and water. Several techniques such as XRD, SEM, TEM, Raman, VSM, TGA, and BET were applied to characterize the adsorbent (MAC). Four important factors of sorbent weight, contact time, initial drug concentration, and temperature were optimized by the Response Surface Methodology technique. The maximum adsorption of 95.125% is attained at the initial drug concentration of 65 mg L-1, sorbent weight of 1.55 g L-1, the contact time of 76.25 min, and at the temperature of 35 degrees C. The results show that the experimental data exhibits the best agreement with the isotherm model of Freundlich. In the kinetics study, the experimental data fit well to the kinetic model of pseudo-second-order. The calculated thermodynamic variable factors designated that the adsorption of erythromycin on magnetic activated carbon is endothermic and spontaneous. Finally, the outcomes of this study display that the magnetic activated carbon from Gogan almond shells is an efficient and effective reusable sorbent for the erythromycin removal from the wastewater.