Indian fly ash has been completely converted to crystalline porous 13X zeolite by NaOH fusion at 600 degrees C followed by hydrothermal treatment at 105 degrees C for 20 h. Obtained materials were characterized by XRD, SEM and surface area measurement. Prepared material was used for the sorption study of different metal ions (CU2+ Co2+ and Ni2+) at different pH, temperature. Thermodynamic data (Delta S, Delta H and Delta G) corresponding to different metal ion uptake were evaluated from Langmuir equation. In all the experiment sorption capacity of prepared zeolite was found to be quite high than that of fly ash at acidic pH. However, the uptake selectivity order for both the materials is Cu2+ > Co2+ > Ni2+. (c) 2006 Elsevier B.V. All rights reserved.