Removal of amoxicillin in aqueous solutions by a chemical activated carbons derived from Jujube nuts: adsorption behaviors, kinetic and thermodynamic studies

The main objective of this work is to assess the efficiency of Amoxicillin (AMX) removal by adsorption on activated carbon (AC). To improve the uptake properties, AC was prepared from Jujube nuts (NJs) and chemically activated by H2SO4. The morphology and physic-chemical properties of the synthesized samples were investigated by XRD and SEM–EDS analyses. The main operational parameters like the contact time, catalyst dose, initial concentration, pH and temperature were optimized step-by-step. The final AMX concentration was analyzed by UV–Vis spectrophotometry. The results showed the efficacy of AC with excellent adsorption properties. The AMX adsorption equilibrium was reached after 20 min of contact time and the Langmuir model gives the most accurate fit of experimental data. To investigate the uptake mechanism, the adsorption constants were determined from the pseudo first order, pseudo second-order and intraparticle diffusion models. It was found that the kinetic of AMX removal is well described by the pseudo second order model. The thermodynamic parameters namely the enthalpy (ΔH° = − 2.099 J K−1 mol−1), entropy (ΔS° = 0.112 J K−1 mol−1) and free energy (ΔG° = − 16.083 to − 17.208 kJ K−1 mol−1) with rising temperature in the range (25–35 °C) indicate an exothermic and spontaneous adsorption. The present study shows that the AC constitutes an efficient process for the removal of AMX from aqueous solution. Finally, the application of this method was extended to real effluents.