Thermodynamic Equilibrium and kinetic study of Nickel and Lead sorption by Zeolite 3A

Abstract

In this study sorption of Ni and Pb ions onto zeolite 3A was investigated at 50 mg/l and different pH to optimize best value for other batch experiments. Therefore, equilibrium isotherms were obtained using batch study by constant pH (6.5 and 5) for Ni and Pb ions respectively, initial concentration 100 mg/l, zeolite dosage and variable temperature and time for thermodynamic and kinetic studies respectively. The results of equilibrium isotherm experiment were analyzed with Langmuir and Freundlich models which show a good fitting with Langmuir model with acceptable regression for Ni and Pb while Freundlich shows good fitting for Pb sorption with a favorable intensity constant (n). Thermodynamic parameters were obtained indicating of endothermic behavior for Ni and exothermic for Pb sorption by Enthalpies values ∆H. Kinetics of the process was studied using Pseudofirst order, Pseudo second order and intra-particle at constant temperature 20C (293 K), at constant condition and variable contact time where the results show smooth increasing of sorption capacity with time until equilibrium and were fitted with pseudo second order model where indicate to chemical sorption  for Ni and Pb by zeolite with acceptable Average relative Error ARE values for obtained theoretical sorption compared to experimental one and This makes it noteworthy that sorption does not for the intra particle diffusion process.