Adsorption of Pb(II) ions from aqueous environment using eco-friendly chitosan schiff's base@Fe3O4 (CSB@Fe3O4) as an adsorbent; kinetics, isotherm and thermodynamic studies

Chitosan and its derivatives can be used to modify magnetic materials to promote the adsorption properties of the magnetic materials for the removal of meal ions. In this study a novel CSB@Fe3O4 was prepared, characterized by XRD, FTIR, SEM, TEM, and VSM analysis and utilized as an adsorbent material for the removal of Pb(II) ions from aqueous solution. Batch studies were performed to evaluate the influences of various experimental parameters like pH, adsorbent dosage, contact time, initial concentration, and the effect of temperature. Optimum conditions for Pb(II) removal were found to be pH 5, adsorbent dosage 0.5 g and equilibrium time of 105 min. The pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to analyze kinetic data. The data fit well with the second-order kinetic model. The equilibrium data were analyzed using the Langmuir, and Freundlich isotherm models. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacity was found to be 83.33 mg/g for CSB@Fe3O4. The calculated thermodynamic parameters ΔG°(−9.728, −9.034 and −7.883 kJ/mol for 303, 313, and 323 K), ΔH° (20.39 kJ/mol) and ΔS° (0.0947 J/mol K) showed that the adsorption of Pb(II) ions were feasible, spontaneous and endothermic in nature.