The influence of chemical conditioning on the removal of copper ions from aqueous solutions by using clinoptilolite

Clinoptilolite, a silica rich variety of the heulendite group of natural zeolites, has the capability to remove trace quantities of cations from aqueous solutions by utilizing the phenomenons of ion-exchange and adsorption. The aim of this study is to investigate the removal of copper ions from aqueous solutions by using the clinoptilolite samples. The results clearly showed that both conditioned and unconditioned forms of the clinoptilolized tuffs have a removal capacity up to 98–99% for low concentrations of metal ions. But the removal capacity decreases for the concentrations of about 500 mg/L when natural forms were used. The chemical conditioning has been found to increase the removal capability of the clinoptilolite to about 50%. The adsorption capacities of the unconditioned, conditioned, and reused forms of the clinoptilolite samples of Cankiri-Corum Basin have also been investigated in this study. The results have been analyzed by Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and BET (Brauner Emmett Teller) adsorption isotherms. Of the model tested, Langmuir, Freundlich, and D-R isotherm expressions were found to better fit the experimental equilibrium data compared with the BET model. © 2008 American Institute of Chemical Engineers Environ Prog, 2009