Taher Yousefi - Materials and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
Mohammad Abbas Mohsen - Materials and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
Hamid Reza Mahmudian - Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran
Meisam Torab-Mostaedi - Materials and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, Tehran, Iran

In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employedfor adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIRtechniques. The Pb(II) adsorption capacity enhanced by 1.8 times from 60 mg/g (natural zeolite) to100 mg/g (modified zeolite) at optimal conditions. Factors such as time, pH, temperature, adsorbentdosage and initial concentration were investigated to optimize the adsorption condition. A fastsorption was observed in the initial contact time and equilibrium was achieved in less than 120 min.The optimum pH for lead removal was between 3 and 6. The adsorption capacity was increased andreached the maximum of 90 % at 2 g/L adsorbent dosage. Also, the adsorption increased as theconcentration increased up to 500 mg/L and the sorption became constant at higher concentration.It was found that the double-exponential model describes the lead sorption kinetics and theLangmuir–model describe the isotherms.

Adsorbent, Cobalt-Hexacyanoferrate, Lead, Modified-Zeolite, Zeolite