Removal of lead ions from aqueous solution by retorted shale

The equilibrium and kinetic properties of Pb2+ ion adsorption by retorted shale (RS) have been investigated during a series of batch adsorption experiments. The effects of pH, contact time and adsorbate initial concentration were evaluated. The pseudo-second-order model was used to predict the rate constants of adsorption system. Langmuir and Freundlich models were used to fit the equilibrium data, which showed that Langmuir best-fitted these data. Thermodynamic parameters of adsorption indicate spontaneous and endothermic nature of the process.