Removal of lead from aqueous solutions u

This study compared the removal of lead from aqueous solutions by cantaloupe peels (CP) as biosorbent against cement kiln dust (CKD) as an industrial byproduct. CP and CKD were characterized by pH, total carbon, nitrogen, and hydrogen content, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Fourier transform infrared (FTIR), surface areas and pore volume to clarify the differences of physicochemical properties. CKD expressed a high affinity for removal of Pb2+ in all examined conditions, while CP was significantly affected, which reflects dissimilarity in the retention mechanisms dependent in CKD and those pursued by CP. The results were confirmed by changes in the FTIR and SEM images before and after sorption experiments. The experimental isotherms data were examined by Freundlich, Langmuir and Temkin isotherm equations. Langmuir isotherm model was more fitted to both sorbents with the highest correlation coefficient. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order, and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to adequately explain the kinetics and correlate with the experimental data well. The thermodynamic parameters revealed that the removal of Pb2+ by both CP and CKD at 298K–323 ± 2 K was a spontaneous and exothermic process. The results exposed that CP and CKD could be used as an efficient sorbent for lead removal from aqueous solution with privileges for CKD in all examined conditions.